Right now, I message my mother and my brother-in-law on Signal, because A) I always have data, don't always have SMS reception (for whatever reason), B) it is safe, secure, E2EE, and C) (and really most importantly) I can (AND DO) separate it from the rest of my SMS/MMS messages (Android Messenger) that get nothing but spam 24/7, to the point where I turn off notifications for AM, as well as have to scroll search for recent messages from people I know, that may want to communicate (most exclusively) through text. So, SMS is clearly not convenient for me whatsoever (most other people get around that (spam texts, etc.) by taking the opposite route of safety/security/etc. by using Facebook Messenger).
So, I am going to try to do some conversions - I am going to try to get (at least!) my two sister's to start using Signal. They DID both download the Google Duo application when I explained to them that I do not have FaceTime, because no iPhone, and FT on macOS is inconvenient to say the least. I think they will go for d/l'ing Signal. I'd probably be the only one on there they communicate with, but, whatever - it would work. Hell, they may even become aware that other people (in our family) are using it, and start messaging one another on there, and ditch FB Messenger or/and iMessage altogether?
It would be nice to have all my communication done on one, easy messenger app (that isn't FB Messenger or iMessage). Oh, and I would ask my therapist to give Signal a try, too (as we communicate through SMS (Android Messenger) exclusively right now, until it comes time for a (virtual, Google Duo) appointment). It's up to her if she gets the app, as she has no obligation to get a dedicated messenger app on her phone just to talk to a client (me), but I will mention it, see what she says.