What I talk about to my friends, girlfriends and family are all on different "privacy levels". If the chats with my friends were disclosed, I'd probably be made a laughing stock at most but it's no big deal. My family ones would probably be most boring, and the ones with my girlfriend could be material for a soap opera, and embarrassing.
But it's not the end of the world if someone at Telegram can read them of if they were disclosed by some hacker group.
My point is that it is an amazing chat app and have way too many benefits for me to not use it, but I _am_ fully aware that there are a chance what I write can be read by someone else, and therefore I take care what I write about.
Oh, and thank you for keeping the discourse on a respectful level. :)