This is kind of a side tangent but apparently the green bubbles/ blue bubbles thing is almost exclusively the US because elsewhere there's a cross-platform messaging app everyone uses instead (LINE, WeChat, WhatsApp, etc.)

Even IN the US, like everyone I talk to is split between Discord, Google Chat, and Facebook Messenger, I pretty much only use SMS for automated messages.

Other than Signal and Apple Messages which of those uses end to end encryption?