How can ‘user facing monitoring’ help a non tech savvy person tell the difference between a fraudulent app that and a real one that otherwise looks the same?

As as for ‘you can just choose the official store’ - it’s not as simple as that. There will be a giant campaign to get people to install alternative stores because the official one is evil and locked down.

People will do so without having the ability to tell which alternative stores are legitimate and which are not.