Changelly has issues and scam accusations as well when the amount involved is much larger so trusting that anonymous for bigger transaction is risky.Like you said I am also using binance nowadays but not too often since I lost interest on every shitcoin now only HODLing the coins.

Now that more and more countries are starting to go cashless (http://www.bbc.com/capital/story/20180427-does-a-cashless-society-benefit-everyone), is it possible that we also start converting to cryptocurrency? If that happens, what do you think are the advantages and disadvantages? Paying virtually is very convenient for me as I do not have to bring cash and it prevents petty theft but what is the disadvantage?

Did you mean every 15 mins bitcoin price will change? If that so, I think it is good for those who invested a huge amount like for maybe 100btc or 200btc. Small changes on a price, it is already a big and huge change in their investment as well. For me, it is really helpful for those big investors that if the price will go up even for 1% then it's already a big change to their investment. Vice verse when the price will go down as well.

This doesn't matter. 15 minutes is really a lot, but it makes no difference actually. You can just reload the page and you will receive an updated rate.

If  a crash within those 15minutes happens (which is highly unlikely), changelly will simple refuse to make your conversion. It is a centralized service, they will look at your rates and refund you.

So it really doesn't matter, and you will not make money by using a long fixed rate.

Doesn't coinpayments lock the rate for like 6 hours? 15 minutes sounds very short especially if the transaction has to confirm within that timespan.

Hy guys. Most of the time I use to trade with altcoins and I use to sell altcoins when they are above ICO price and giving some profit. I do not hold atlcoins for long time. What if you have some altcoins, what will be your strategy to use that coins? Is there any specific best time for every altcoin and when it is going well and we should sell ?? 

Back in the day, Vitalik once said that crypto will be going to zero. There has been many concerns about the longevity of cryptocurrency as a serious form of money, given that it's relatively unstable within the mainstream world. It's been 10 years since Bitcoin was created where crypto has had its ups and downs. However, many are afraid that crypto will be going to zero as the blockchain hype ends and governments start rolling their own digital currencies. When we take a look at most cryptocurrencies on the market, most of them aren't even useful at all. Perhaps, the only one is Bitcoin but it's terrible as a currency for daily transactions.

Which is why, I'm starting to wonder if crypto will really go to zero in the future? If this happens, then most of us will lose our hard-earned money as crypto becomes worthless. What are your thoughts?

Yes. Life after death. Because you are too much of an egoist to think about the world without you.