I observed the impact of WhatsApp (without payment) in indonesia where free basics / internet.org made WhatsApp the ubiquitous communication channel for talking to the hostels landlord, the taxi driver, the restaurant, ... using anything else causes costs, which they wanted to avoid. If that now also handles the payment for the taxi or hotel or whatever it's the clear choice ... If I like it or not.

For my agenda I'd rip Facebook apart. But that only counts a little in reality.