I understand the reasoning of depending too much on Telegram. But initially considering security and privacy aspects of Telegram, we thought it was the best option to provide and private way for people to exchange BTC (localbitcoins & others gets frequently blocked and recently they also stopped cash deals!).
Telegram is a honeypot for governments, just like any other social media platform is. In that regard, the privacy aspect you seem to have liked is very relative.
The act (i.e. being an unlicensed money transmitter) is illegal on its own, and actually pretty dangerous as well if you put so much faith in a social media platform. I personally don't care about what people do, but if there is one thing governments are actively fighting against, then it's entities facilitating trades in this manner. It's like playing Russian roulette. It either goes well or horribly bad.