Im not terribly familiar with the HW keys; Are you able to get multiple keys? I would worry that it would be similar to TOTP, in that if you lose/misplace/don’t have the device then you would be locked out.

And I probably wouldn’t switch banks for it, it would depend on how much more secure I perceived it and any other bank differences.

I agree, it’s not a perfect system. Even if you do have multiple devices - you may be locked out if you lose your phone while traveling, can have multiple failures.

Although I don’t know what is remotely secure and is elderly friendly. Email or SMS 2FA would have been the closest in mind, but it’s not secure, and plenty of elderly struggle with both.

You can use TOTP with multiple devices. For example with an app on your phone and something like KeePass on your laptop/desktop.

Still not convenient since you don’t walk around with this in your pocket - but it doesn’t have to be just one point of failure.