No strong opinion on it specifically, but you are trusting the author of that extension to never abuse access to your banking info, so as long as you trust them with all your money, you're golden!

Any extension with post-decryption ability to read and modify everything on all websites could, if they choose, see any sensitive info you do, and subtly even change it without your knowledge.

And I'm not saying uBlock would, or that as a super popular extension it likely wouldn't be discovered quickly, but arguably they can because you've given the extension the ability to see and rewrite your entire reality.