You are right in saying that you can make predictions on crypto, however the concern is not about making predictions but rather accuracy with which you make these predictions. From my point of view i think that because crypto is a decentralized platform that there is a lot of human psychology involved in predicting the price of crypto because you have to predict how people will respond to a crypto and this does not seem possible to me.
I am not even trading crypto right now but I am actually trying to practice predicting crypto right now and I can say that almost 60 percent of my predictions are right even though I am not an expert crypto trader. I try my best to analyse charts and crypto coins data. Just imagine how accurate expert crypto traders would be!