Aren't banks sort of the poster children for legacy practices though? Only works with this or that browser, here are some weird password rules, yes I have an SVGA monitor, no I can't search older than 90 days, etc. I'm used to turning off my modern expectations and just getting into the 20 years-old flow for the time I'm logged into the average bank. No, I don't want to switch banks (where my mortgage and dozens of ACH linkages are set up) to have better ad blocker compatibility.
They aren't using advertisers. They're incorrectly* using user behavior instrumentation for diagnostics and anti-fraud, especially blocking on login if tracking is disabled as they are trying to prevent credential stuffing bots.
* Bug, or feature, many fail if the tracking is blocked, due to other code that assumes it's there or depends on it. They fail closed instead of fail open.
