That is why you need to conduct thorough research about the altcoins you want to invest to save money and time. There are many altcoins which are shit coins as well as great alternative coins. You need to be careful.
Actually not all altcoins are useless they are some also are can getting you to become rich.
We all know they are to many altcoins now are become shitcoins in the end so if we dont want that kind of altcoins as you said need some research and careful on which altcoins are we need to choose for trading.
Holding shitcoins will not make enough return on the investment but having a strong coin on the portfolio can talk for itself with numbers. In trading numbers never lie and holding coins of potentially strong projects is better than other choices.