If they accept Bitcoin payments, they have to think about Bitcoin refunds, which, to my mind, won't be an easy thing to do
Just refund in cash or subtract onchain tx fees. Not a big deal imho
I remember that this has happened with those hacked exchanges and when the refund came, they've paid in cash and not with an actual crypto that was lost. So, most customers have their Bitcoin stolen and when the issuer have to refund them, it's decided that they'll get paid on the actual price of the crypto they've held. Because if they'll pay in current value and actual crypto, it has grown tremendously and that's a huge loss for that exchange.