You might be surprised at how many “normies” are getting on board with Signal.
The user base pales in comparison to WhatsApp but it did double in the last couple of years.
https://xkcd.com/1102/
What I mean is that in Mexico, Brazil, and many other countries, WhatsApp is the de facto messaging standard. Businesses expect you to have it, restaurant ordering is integrated with it, etc.
In the US, we don't have anything except SMS/RCS.
If you’re not a nerd, signal is like a batlight for people doing stupid shit.
In the US we don't reliably use WhatsApp, iMessage is locked down, and Signal, etc., are just for tech bros or political hacks. Yet, everyone wants to text instead of call, so we are in this world where we need to make RCS work, and they are just not putting in the effort.