Just like stock, you can invest all your money for a coin code if you really trust. But that would be very dangerous. One can make sure that the coin will not fall down to 0 a day.
The advice is to diversify your portfolio. That will help reduce the risk. You do not earn much but if not lost also much.
It is not always necessary to stick to one especially in crypo market, I agree that we need to explore things out. Don't just focus in a single reference, it is also risky just like bank account, don't just depend on a single bank as if that bank suddenly fire out, there is just a minimum amount that you can recover so if you have millions there, you cannot get it all.