While I try to promote @SignalMessenger@twitter.com and @email@example.com, most of my contacts are using Whatsapp only, a few only Facebook messenger and one only google Allo.
Nevertheless, thanks to the 20-30 people using Signal with me. (And I'm mostly alone on Wire).
I just counted them. 50 of my contacts with their phone number in my address book have a @SignalMessenger@twitter.com account.