I'm with BNZ and I find their app based 2FA really good, but I totally get that installing an iPhone app isn't a workable solution for everyone. My father buys complicated phones/computers, gets totally out of his depth with them, then gives up and reverts back to old fashioned ways of doing things. He is a good example of someone who could easily use SMS but probably not an app.

In my particular case, having set up 2FA on the app, I would hope that BNZ would not allow any subsequent 2FA or password reset via SMS.