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.
and just like stocks what you are suggesting here is this:
"when you invest in stocks you should diversify into penny stocks too if you want to reduce the risk".
do you see how it doesn't make any sense now?
that is the issue with altcoins, they are more like penny stocks market than a real market. and then if you consider the level of manipulate and pump and dump that is happening in altcoins you can realize that when you "diversify your money" it is best that your cart contains: bitcoin, stocks, gold,... instead of being: bitcoin, altcoin1, altcoin2, ... altcoin10,....
In the face of unpredictable BTC investment risk, the establishment of a portfolio investment plan is of great significance. Portfolio investment will not only hurt your earnings. On the contrary, it indirectly increases the expected return by reducing the "risk of diversification."