Talk to anyone in latin america, you must use whatsapp. There's no avoiding it. Some have tried Telegram a while ago, but most have reverted back to their usual whatsapp or facebook messenger. It's crazy.

No, not regionally, as Whatsapp is probably used most. It is more individuals who decided not to use Facebook related products. Luckily, about 90% of my contacts are on Telegram. It's a bit sad that a proprietary product that leaks metadata could be so widely used. If there was going to be a single "one product" I'd rather prefer that to be an open standard protocol. Those protocols exist, but are not in broad use. But the W3C standard for social networking, really needs to also cover chat messengers.