When the App Store was launched, most apps had a single backend they connected to. I’m thinking of say the FB app or the Google maps app which only talked to Fb and Google respectively.

These payment apps integrate with a much wider arrays of backends from multiple providers and allow you perform many more unique use cases. E.g., making charitable donations and paying an insurance premium are unrelated but the Indian payment app I’m thinking of enables it.

This brings it closer to being an “everything” app.