They might actively use it but not because they want to.
In fact, Brazil's most popular chatting app that is recently banned there doesn't have multi-device sync. Hangouts does. Everyone could use hangouts, but not nearly as many people do.
Using your phone number and address book to find contacts is what made it really easy for me. Also, iPhone users don't use Hangouts, but were somehow "forced" to use Whatsapp to talk to people on Android phones.
In fact, Brazil's most popular chatting app that is recently banned there doesn't have multi-device sync. Hangouts does. Everyone could use hangouts, but not nearly as many people do.