Well, Facebook, Instagram, Facebook Messenger, and now Whatsapp. I really can't stand using an app that has ads. I really really could use them if they weren't so intrusive or annoying, Whatsapp it's the only META app that I'm still using due my close relations do use it.
Which App do you use to chat with your closest people? You simple don't? Or you use another medium to get in touch? I always can make a call to my relatives, but there are people, like my gf, which I need to communicate in more than one way, send audios, photos, videos, etc. Every reply it's appreciate it.
When I quit meta, I wanted people to use signal, but my dad refused to move to another app. We just talk via sms now. My wife and her family overseas are on Line, which is kind of like a Japanese whatsapp (maybe closer to WeChat). It has e2e encryption but it could be the same story with WhatsApp where you don't really know if they're reading your messages or not
Would rather use WhatsApp then SMS. Its much more secure and private and doesn't cost money. Although if RCS is an option it could be used instead of SMS or WhatsApp.
Signal. It's in the perfect middle ground of security and usability. Security enthusiasts will tell you it isn't good enough. It's fine, and it's certainly better than Facebook Messenger.
I've wrangled over this very question for years. I've looked at all the research, I've read all of the articles and I've witnessed all of the armchair security 'experts' make their claims one way or the other. I got so exhausted bouncing back and forth between a dozen screamed opinions, I walked away. In the end, I decided to go with Signal and it has served my needs for a secure and private instant messenger with no ads or shady crypto-scams without fail.
Kind of a fair point though I think users should be able to make that choice for themselves. If they do not want that, they can just not use it - the app clearly shows whether chats are encrypted or not and I'm pretty sure you could also disable the plain-email feature.