Leaking information about a personal account when it has only been used authorized for the purposes of transfer seems to be a P0 bug to me, from a disinterested third-party point of view. If I authorize a transfer of $10k to my startup and for some reason my co-founder is able to see that my personal account balance at Bank of America is $400k, that sounds like...a massive leak of information that I didn't authorize.

Or do I have a mistaken view of what the problem is?

We also experienced the personal balance privacy issue where we didn't expect to see each other's balances but was too late by then.