He really gave you a good answer, see something no matter how good you are in trading there is a point that thing's will go Down and you will not see it coming. I have not have the idea to make loan's in a bank and use it for crypto is really insecure and risky to my own opinion I won't advice or recommend that.
in my opinion
If the person is managing the risks well and is using stop lose there is no need to hesitate
Especially if he wants trading to be his primary source of income