A lot of that is security theater at its best. However given the forced attack surface I would imagine that there is a hard push from authoritarians and the finance world to make a "secure chain" from service to screen.

My guess: They're afraid that the scammers are going to mirror the screen and remote control access to the app. (More orgs are moving to app/phone based assumptions because it saves the org money and pushes cost on the consumer) Instead of providing protections from account take over.. we're going to get devices we don't own and we have to to pay for, maintain and pay for services to get a terminal to your own bank account. Additionally, there are many dictatorships, like the UK, North Korea, etc, that are very adimate that you don't look at things without their permission. So they're trying to close the gap of avoiding age verification bypasses with VPNs.