I seriously doubt that, I've lived in 3 of the countries (fairly large ones) where WhatsApp is THE communications and in all of those, at least to my knowledge,

I seriously doubt that, I've lived in 3 of the countries (fairly large ones) where WhatsApp is THE communications and in all of those, at least to my knowledge, most (mostly young) people send money electronically through banks, sometimes more modern digital versions like Nubank in Brazil, but there's no all-encompassing default solution.