> If your issuer contractually offers zero liability for debit fraud, that is just as binding as regulations – and most do.
Every bank card or account I've ever had regularly send out notices saying they have changed their terms of service and your continued use of the account indicates your agreement to the new terms.
In other words they can change those any time they want unilaterally and you probably won't even notice (because who reads those terms of service?)
You may also want to read all the fine print to see if they carve themselves any exceptions.
The great benefit of the protections under credit card regulations is not having to worry about any such shenanigans. The bank can't change the regulation so you know you're always protected, full stop.
Also remember that fraud on a debit card hits your account balance immediately, even if you can later argue to have it credited. Fraud on a credit card simply hits the credit card and can't touch your real money. Think of a credit card as cloudflare layer for your bank account agains fraud DoS.
I'm always very puzzled as why in the US one would ever use a debit card (I say US because I'm not familiar with regulations in other countries). A credit card offers stronger protections, stronger account isolation and cash back rewards.