[-mlv]

There are plenty of TOTP 2FA apps that work across different platforms, open source ones too, it's just a couple dozen LoC for the core functionality.

[rendaw]

I think GP meant "installing the bank's app as 2FA", not standard 2fa. I think the idea is that generally banks are resistant to and incompetent at technology, so a paper solution that avoids bad software decisions is laudable.