It think you’re confusing security (in terms of how easy it is to impersonate you to access your bank account) with privacy and the level of requirements on the user that go with it - the impact on banking security of the bank having your phone number is basically zero since generally lots individuals and companies who are far less security conscious than banks have that number.

That said, I think you make a good point (people shouldn’t need a mobile phone to be able to use online banking and even if they do have one, they shouldn’t need to provide it to the bank) and I agree with that point, though it’s parallel to the point I’m making rather than going against it.

I certainly don’t see how that collides with the last paragraph of my original post which is about how the original thread poster has problems working with banks which “require a separate device that looks like a calculator to use online banking” which is an element of the most secure method of all (which I described in my original post) and is not at all 2FA but something altogether different and hence does not require providing a person’s phone to the bank. I mean, some banks might put 2FA on top of that challenge-response card authentication methods, but they’re not required to do so in Europe (I know, because one of the banks in Europe with which I have an account uses that method and has no 2FA, whilst a different one has 2FA instead of that method) - as far as I know (not sure, though) banks in Europe are only forced to use 2FA if all they had before that for “security” was something even worse such as username + password authentication, because without those regulations plenty of banks would still be using said even worse method (certainly that was the case with my second bank, who back in the late 2010s still used ridiculously insecure online authentication and only started using 2FA because they were forced to)