The problem that unless you are going to blow up the Empire State Building it's very hard to convince people to use yet another not to mention switch to a different messaging app.

What happens is that the person who does it effectively being cut out of the loop with maybe a handful of their contacts becoming partial converts that might serve as human routers for a while.

WhatsApp and Signal work because they are easy they are mom/grandpa proof and they have a huge user base.