Because few people care about privacy but many care about UI, UX & features. Telegram is better there than any other chat app by a susbstantial margin.
This, unfortunately. Matrix (Element) is ever so sloowly getting there, it's slightly better than Signal now in some areas and worse in others, but neither (nor whatsapp or any other messenger) come close to Telegram.
Wire is also a good contender but they seem to have found that if you don't sell user data, there is little money to be made from personal accounts and are focusing more on business accounts. You can still register and use it as an individual, though (and I continue to do so). It has more features than Signal and isn't funded by Facebook so that's a plus, but the UX is slightly worse than Signal.
Makes you wonder what Telegram is going to make money with though. It's a huge liability for me, just so damn convenient... Need to find a better alternative.
They're totally different apps! Signal's focus is 1-to-1 encrypted chats. Telegram's focus is broadcasting messages and group chats. One of them is a secure messenger, the other is a social media network on top of a messaging app.
Because Signal is virtually unknown here. Telegram has a small, but growing following. I'm aware that Telegram uses homegrown encryption which is not ideal.
In the same way that FB, Whatsapp, and pretty much every other app works. I doubt there are any chat apps that don't encrypt between the client and server.
IMHO, it is NOT encrypted, unless the service provider (also can't read your message). A promise from a Russian based company (the Facebook of Russia) doesn't put any assurances for me.
why Signal and not wire? (no sim card needed), No need to allow access to your address book to make group chat. Works in browser, ios, android, desktop app. Using signal protocol. And you can draw in it.
why wire and not lockdown?
why lockdown and not matrix?
why matrix and not IRC on a self-hosted server?
why IRC and not HF packet radio
why HF packet radio and not OTP notes on flashpaper delivered by carrier pigeon?
this is the current problem i have with chat. there are too many options.
I've been using Wire for a few years and the experience is solid. No need for phone numbers anymore, just @handle, and it does multi-device encryption and backup. Its search is very fast, even for large number of messages. Good support for attachments and superb audio and video.
On the flip side, it's not very customizable and doesn't have a lot of the more "modern" UX goodies like emoji reactions or threads. But it's overall very good and I see no reason to change.