It's not an exchange. It's a loan with a collateral. It's only an "exchange" if you get liquidated, which means that you were forced to sell it at a loss.
Doesn't this assume you only get liquidated below your initial purchase price?
With something as volatile as cryptocurrency it's not exactly a crazy idea that you'd buy at say $30k, take a loan at $60k and get liquidated at $50k and get stuck with a big tax bill
