I am thinking about quitting telegram and these kind of services altogether.
If you think about it, they don't really provide any feature, that emails don't (maybe to make a voice call. But I can use plain old phone function for that)
The only thing I can think of is the speed it takes from me sending till the other user gets a notification on their phone. But I have to test this and check where the bottleneck is.
This is a private Mastodon instance. Federates with anyone but does not accept new users.