Telegram is not at all secure compared to Signal (in theory). However it has an awesome UI and lots of nice features (most of which are lost using secret chats).

For the longest time these were exclusive features to telegram compared to Signal:

* Delete messages at other party ("undo"), critical for deleting accidentally sent nudes. * Username only communication * Stickers (silly, but well kinda fun) * Bots (very easy to make your computer talk to your phone or a group this way) * link preview * Self messages as easy link/file sharing between devices. Super useful.

Signal is slowly catching up, but it's so buggy at times, I am starting to really hate it/distrust it (I also dislike MM's personality/opinions). Matrix seems to move at a better pace, with more useful features already (e.g edit, markdown, some fun things). I am happy to get rid of telegram for Matrix. One feature better then the other already: resync of lost messages from the distributed network and no reliance on telephone numbers as UID.