Also the bank card is really part of the bank system. It doesn't do anything else, and it has to interoperate exactly as they want it to. While I may feel the right to hack on it, I'd do so entirely at my own risk. It's probably better that I don't mess with it as long as it fulfils its purpose. I can use my own device for my own stuff.

I feel the same way about ISP modems (not routers). As long as I get an Ethernet port and the modem isn't doing anything untoward, I don't see any problem with letting the ISP's network termination equipment exist inside my house. Some people think there should be a right to hand off the connection as DSL or fiber and buy your own modem, and I think you should be allowed to do that at your own risk, but I don't think the ISP should have to support it. Particularly with PON fiber or CATV, it's actually a bit dangerous to let the customer use random modems as it's a shared medium with half your street and you wouldn't want to jam them.