Useful in what ways? I see that Ethereum and bitcoin are both coins that are needed by many people, it's just that in different ways, if Ethereum is useful because of its technology, while Bitcoin is useful because it is the pioneer and at the same time the foundation of altcoin prices, I'm not even sure there will be altcoins if Bitcoin doesn't exist 

Of course not all of them, but I believe what the OP meant was mostly FOMO. I also believe that FOMO is a bad trend and should not be followed, as most FOMO ends in a loss. FOMO is the biggest enemy of traders and investors alike, because FOMO can be easily played by whales, so be careful if you trade/nvest based on FOMO trends.

Not only is it safe, but the coin price movement is healthier and the profit that you get is likely to be stable. Investing in coins that have little liquidity is a bad choice, because coins like these are unstable in price and often go up and down very steeply, if you go up you might be happy because you get a lot of profit, but if you go down you can lose more than 50% of your funds.

No, it's just a matter of market capitalization, you can see on the chart of bitcoin dominance, when the market cap of bitcoin goes down it indirectly moves the market cap in altcoins, and this is the only way that altcoins can go to the moon.
And what do you mean $9? bitcoin price is now $49k.

If once or twice is natural, but if someone trades and loses many times it means there is something wrong with the way he trades. Discipline should solve the problems of novice traders, but unfortunately very few traders learn about emotional management as well as discipline, and for this reason many traders stop trading because they often lose more than they make a profit.

Greed is a mistake that is often made by traders, greed and breaking the rules that have been made . If you are not sure about investing or trading short-term, then prefer long-term investing, long-term investing is not much different from trading, because you are buying and selling, it's just different from the time frame you use.

Do you think that fundamental analysis and technical analysis are not needed if you want to invest in the long term?
In my opinion, finding a good support area and finding a golden opportunity to buy requires technical analysis, so that you can determine the area of support and can see where the market trend will move.

Bitcoin Gold and Bitcoin Diamond are not much different, I mean the development, maybe a few years ago BTG was good and became a potential coin, but after DeFi I didn't see anything interesting about BTG (this is my personal opinion),
and another reason, when yesterday I made a deposit on the exchange using BTG it took more than 30 confirmations about more than 6 hours to enter my exchange wallet.
In my opinion, before talking about technology, I think the issue of transaction speed and confirmation on exchange must be resolved first.

It's difficult to determine, because the topic you made is a little abstract, what do you mean by friendly? is it close to bitcoin? or what? because of many factors with which to look at it. But if based on market cap, only ethereum is so far close to bitcoin. Because since a few years ago, ethereum was still able to stay in the market capitalization ranking.

I can't possibly just leave crypto. If there is news about the government regulating cryptocurrency I have to verify it first, I am sure there are certain reasons and also not everything will be regulated by the government, or maybe the news isn't about bad rules, maybe the rules are in favor of cryptocurrency.

It is very rare for a new project to use the TRC20 network, but since ethereum gas is expensive, many projects have tried to wrap coins in the TRC20 network. I think you can now try choosing tokens from TRC20, because the transaction fees are cheap, so you can easily sell your tokens.
Maybe JST or BTT can be an option, because the price is still cheap

At my place, transactions using bitcoin are prohibited, because it will violate the law and can only make transactions using FIAT.
But I personally work and focus on cryptocurrency, and every month I get a bitcoin salary, if I don't buy something online, I usually convert my bitcoins to FIAT and withdraw it to my ATM.

It is impossible for Elon Musk to do FOMO without making prior preparations, they and their entire team have of course planned this, they are very easy to take profit, because they are the ones who drive and control market sentiment,
Now you don't need to hesitate if you want to buy coins for short-term trading, just wait for Elon Musk to make a word on twitter and the coin price will go to the moon.

I see coins that have strong candidates to become the next Ethereum are Plokadot, Binance coin and also Tron coin, there are other coins such as Xcash and Minter ,, it's just that these two coins have poor marketing, so maybe it is more suitable to be the next Ripple .

Are you sure just by creating threads on the bitcointalk forums and groups in telegram the project is legit?
I'm not sure about that, I often see projects that have threads in forums, have a large number of subscribers and have websites and products but they end up being a scam.
so you have to be careful, because there is no specific standard to see a project as legit or not,

I agree with you, USDT is better because many coins are paired with USDT, so it is easy to buy and sell them again.
But if for DAI transparency it is better, because there are issues that say if USDT is a stable coin that is not backed up with money, in other words it is printed unlimitedly depending on the CEO policy.

BNB is indeed good and has potential in the future, it's just that BNB is useful on Binance, different from Ethereum or Polkadot ,,
But if based on the price, BNB should have been almost 1000 usd, because the maximum supply is not much different from ethereum.

This is a problem experienced by beginners, news about anything is very easy for a beginner to believe, that's why someone like us who has been in the cryptocurrency world for a long time provides correct information about this,
I personally created a special group that provides education to beginners, so they don't easily believe in anything and do their own research before making a decision.

This is a problem that many people complain about, the only solution is that you have to wait for the right time when the gas fees go down and then you swap use uniswap or send it to exchange, after that if you want to hold tokens I suggest you only hold tokens from the TRC20 network or BSC network, because of the fees of both networks it's very cheap.

Doge is not a good choice of coins for investment, because doge is too much manipulation from the whales, to be safer choose coins that have strong fundamentals, such as Polkadot or Ethereum. But for ethereum now has a problem with its transaction fees.