The reason that Whatsapp massively took off in certain parts of the world, and to an extent even replaced the public-telephone system (e.g. restaurants and other local businesses may even want to be contacted by Whatsapp, not phone), is because SMS is expensive, but data is not. Sure, you might be in a part of the world where SMS is a viable option, but for many people it no longer is, and instead of asking for SMS you might suggest an alternative like Telegram or Signal.

I've been trying to get people to use Telegram for years. For whatever reason, everybody wants to hear why Telegram is acceptable to me but WhatsApp is not, but they are not patient enough to even try to digest the answer in the majority of cases. And people will install any privacy-invading games or icon packs with no problem, but not another instant messenger. I have no idea what is behind this phenomenon.