looks like rendering adblockers extensions obsolete with manifest-v3 was not enough so now they try to implement DRM into the browser giving the ability to any website to refuse traffic to you if you don't run a complaint browser ( cough...firefox )
here is an article in hacker news since i'm sure they can explain this to you better than i.
and also some github docs
oh, I also want to point out that you completely ignored my question; you said "There would have to be very significant reasons" and I asked what that was, and instead of responding with a clarification on what is required as a reason for a bank to actually do the thing, you attacked my position asking for more clarity on which banks were actually doing this, I'm sure in an effort to minimize the scale at which my experience is relevant, yet other lemmings have already chimed in to say that they have also witnessed the same lazy behavior.
Classic misdirection. So, what justification is required for banks to actually innovate? The only thing I've seen from banks is them trying everything they can not to; so I'm genuinely curious what justification is required to actually make a bank do something.