I had to replace a credit card yesterday. Part of the default flow involves the call center sending a notification to your app. When I told them my android version was too old, it took them twenty minutes to find out they could instead send a text message. That text message sends you to a photo-and-id verification service, but that's another issue.

Soon, there won't even be an alternative flow. There are a lot of places where there already isn't.

Are you sure? This seems like a forum with a lot of early adopters and a lot of late adopters still use browsers, email, text messages. Like, let me guess that your credit cars isn't capitol one. Not that it should be, but that would be more "normie".