I work in the digital security sector and I'm not this paranoid.

Banks are about making money, full stop. It does not serve their interests or the interests of their investors to proactively spy on customers for the state unless they are a state-controlled organization like you'd find in places like Russia and China. Will they respond to requests from law enforcement? For sure. They want to maintain good relationships for help with things like fraud and other financial crimes. But they are not in the business of doing the cops' work for them for free.

There are so many reasons why organizations conduct various forms of user research unrelated to marketing too.

As another user mentioned, A/B testing a mail format is one example. Measuring click-through rates on various types of messages to track what works and what doesn't is always valuable. There's also value in getting browser/device statistics - how many people open emails on their mobile device vs web browser vs desktop email client, etc. And so on, and so on, and so on.

Banks are about making money. User research helps companies make money by making data-informed decisions that drive profitability. It's really that simple.

And again, tracking pixels are extremely fragile. They really only work in aggregate over a large population for statistical analysis. They're way too unreliable for much else. There are lots of better ways to achieve the same and better results if your goal is monitoring individuals

I'm not trying to discourage you from protecting your privacy by blocking trackers. I do it myself in various ways because it is a good practice to protect your privacy, identity, etc.

I'm just telling you that they didn't freeze your bank account because of the tracking in emails.