You said it yourself. Crypto has nothing to stabilise its value. It is entirely speculative. There is three options to make money with crypto. Sell it to someone that believes in it more than you do. Sell it to someone that believes he can make more of a quick buck than you, or have the gamble work, that it ends up becoming a legit payment system and have the value explode and stabilise there.
In the first two cases you just try to fuck over another gambler. In the third case you yourself gamble.
It is always possible that the hype collapses or crypto gets banned globally. Whoever is left holding it then got scammed by the others.
While in the beginning many investors believed it to become a viable payment system eventually, now most are just looking to not be the last in line to get scammed.