Okay look. *I* don't use # ( and same for # ), because I don't want to give my telephone number to anyone except family and close friends. I have enough personal contacts that do use them so that they'd be personally useful if I didn't have that unbreakable obstacle.

But I don't object to others choosing such end-to-end encrypted messengers over messaging apps such as (for example) #

I personally use #, #, #, and # (I tried #, but it wasn't very usable yet; none of my contacts were willing to try # or #) I've even considered getting a Google account again so I can use whatever their latest incarnation of messaging is (just because almost everyone I know has a Google account).

It does bother me that Signal and Telegram and most other messaging services are centralized and non-federated.

It seems we haven't learned from the 1990s & early 2000s when some friends had AOL Instant Messenger (AIM), some had MSN Messenger, some had Yahoo Messenger, some had ICQ, and a few had various other walled garden messengers (such as Excite's messenger). If I wanted to talk with all my friends, I needed to have accounts on every possible service. I should be able to communicate with my friends from whatever service I choose to use to whatever services they choose to use and not have to create accounts on every possible service.

But that's a matter of educating our friends and family, not of dogmatically refusing to communicate with them on any service they might use.