If a machine is going to have multiple users (all my computers have multiple profiles for family members) all those users have to be called something, and I’ve not got the energy or the creativity to come up with fun and funky usernames for every system when my actual name is more than good enough.
The UK isn’t quite that far, but it’s absolutely the dominant text messaging and calling app in the UK. Nobody uses the built in Android or Apple tools anymore, and I’m as likely to receive a WhatsApp voice call as an actual phone call these days.
I have Signal on my phone, but I’ve literally never had a cause to use it; I’ve simply got no contacts on there.