I think it's worth it.
Just simply send a link along with that's generally better and that lots of people are moving over. Watomatic could be looked into as a way to automatically remind people you are on signal when they go to Facebook you. It would then prompt then to install signal.
I take the attitude if they want to contact me either, phone, email or text.
Maybe same text just laforge format. Fediverce is star trek.