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.

Nothing is stopping you. You're free to use a desktop web app that either doesn't work or is terribly slow or has limited features on a mobile web browser. I'd love it if all apps were PWAs but that is not the case.

The websites don't have feature parity with the apps these days. Things like being able to deposit a cheque aren't available among other things.

Some banks are app only and/or build MFA functionality into their apps.

> What's stopping me from using a browser to log in to my bank?

The "security module" they require you to install on your computer. In the past, when browsers had plugins, this was a browser plugin; nowadays, it's an always-on service (running as root) which exposes a local HTTP server which the bank site connects to to validate your computer. For an example from a major bank in this country (the same "security module" is used by several banks in this country), https://seg.bb.com.br/home.html is the diagnostic page for that "security module" (the FAQ page there has links to the installers).

The bank website typically needs the app to enable two factor authentication in a lot of places.

For eg. There's no browser based alternative to make UPI payments that i know of.

In many countries, all major local banks require their phone app as the second factor to log in to the browser version of their online banking. Sometimes functionality is removed from the browser version and made available only in the phone app.

The 2FA code you need to get from the phone app to log in on a desktop. It isn't 2005 any more.

Well, it's kinda hard to scan a QR code displayed on your screen when the camera is attached to its back (semi-joking)

The bank itself. They want to see where are you, what you do and snoop on anything they can about you. Having a spywa^W sorry, bank app is the best way to do that.

Source: my bank which recently 'upgraded' a browser version to a glorified SPA which even renders as a vertical oriented app on a landscape 4K monitor.