Is it possibly a quirk of your country of origin? I'm assuming you're an EU citizen, and I'm not sure how EU rules work, but perhaps your country has overriding rules that prohibit deposits from being required? Or perhaps paying "via bank" has some implicit damage deposit mechanism going on? Can we ask for you to steal a bathrobe next time to see what happens, in the name of science? :D

I do most of my bookings from US soil with a credit card for guarantee or pre-pay (I do a mix of both), but never direct bank account. So one could imagine the rules for my bookings are different than yours. However I do sometimes make bookings mid-trip, and have not noticed a different damage policy, and, in Europe, I check in with an EU passport so I'd probably be subjected to the same rules/policies as any other European.