I stay away from everything crypto but I don't see the difference. In both cases if they didn't make it right you'd go to the courts and make your case that they are at fault and owe you compensation.
A safe deposit box may be affected by other things and if those things happen they don't have to "make it right", if you go to the courts and make your case you may find that they are not at fault and you are not owed any compensation.
There is a long history here of once trusted institutions turning out to be fraudulent.