they steal - which is why there are several different types of crypto in there. After a while, they will either convert it all to another form of crypto, or cash those ones out directly - depending on the wallet and its capability. Once they access someone's wallet, they transfer every type of crypto in that wallet to that hot wallet address.
It could even be a multiple person job, and they are pooling the money to split, or they pool the money for someone else who is giving them a cut.
Since I got into crypto a little while ago, I have come to realize how easy it is to scam people, and it is still a pretty unregulated thing, so any repercussions would be hard to come by. If I was a scumbag of a person, it would be my preferred way of screwing others over right now.