Altcoins don't have a real and practical reason to exist. They just copied Bitcoin to speculate on its trend. The strongest one is Ethereum, and that is just because developers use its network to launch their own altcoins. Therefore, you can't expect much from them... As you can see, they are totally vulnerable to Bitcoin's fluctuations, so when BTC crashes, the altcoins market crash as well, and when Bitcoin pumps, the altcoins market as a whole rises too.
They don't have their own life, so if you are serious about investing your money, you should focus in Bitcoin and allocate just a minor percentage to altcoins, and mainly for experimentation reasons.
I refused to agree with this, even Bitcoin does not have practical reason to exist but it's doing well. One bit advantage of Bitcoin over other coin is the fact that Bitcoin is decentralized, you cannot compare it with Ethereum and some alts that has teams. Coins with teams tend to collapse because anytime the team want to make decisions, they don't have the interest of the people, it's always about them and that's why they don't end well.
If you look at Bitcoin, everything is different, the team did Ico and raise millions, Bitcoin didn't raise any money, Ethereum allocate some coins to the team, there is no any allocation to anyone in Bitcoin. So when people are trying to shill Ethereum, you are also making the teams richer, while in Bitcoin it's a collective people that makes the price of Bitcoin to go up and the more the demand, the higher it goes, Bitcoin serves the people better than Ethereum and other alts.