alt Hacker NewsI suspect that especially banks have paranoid lawyers that probably don't understand the situation entirely, and perhaps because of that, mandate that all means have to be used to prevent non-official builds from being used, so that they cannot be sued (for some reason) if "something" goes wrong. Though I don't know if they are consistent and also apply the same reasoning to phones that don't have active security updates any more.
I feel like "the lawyers told us to do something stupid for no legitimate reason" is just one part of a bureaucracy trying to blame another part for the fact that the bureaucracy itself is doing something stupid for no legitimate reason.