Using your debit card is not like using your credit card. Debit card transactions are processed by Visa for instance, but its still not a credit transaction and therefore you are not protected under the federal credit card laws.
Like you just said, its up to the discretion of your bank to reimburse you. Very different than you not paying your credit card and disputing any fraudulent charges. I dont read the fine print on my bank account, do you? Some of the definitions around your liability are with how responsible you were with your debit card. Lets assume you left your bank debit card at a bar, and due to being drunk, you didn’t realize you left it until a day later. In the meantime, someone went out and bought thousands of dollars, cleaning out your bank account. Can you be held liable for this because technically you weren’t being responsible?
Numbers are often stolen while you are in possession of your card, compromised at big box stores, not to mention stolen directly by people who come in contact with your card. I personally do not want to discover that my checking account has been cleaned out with fraudulent “charges” that really aren’t charges but debit withdrawals.
I preach this to people who’ve had their debit card numbers stolen. I do not even have a Visa logo on my bank debit cards.