It's good for things like Android to iOS. Others iMessage is a goto for phone to phone comms on IOS. Telegram allows usernames but their stuff isn't encrypted by default and is run by shady people.
Discussion
A trust worthy, privacy first telegram like application would be amazing. Something that I could (optionally) add a phone number to get get connected with people that have me in their contacts, but also be able to share a handle or pub key to connect with people I don’t want to share my phone number with.