People pointed to me, that such bot already exists: https://t.me/BTC_CHANGE_BOT

I went through and it looks great, main difference from my implementation, which I noticed so far:
I proxy all messages through the bot, to simplify conflict resolution in case of trouble and to allow some privacy to users who don't want random contacts in their Telegram.
Which way do you think is better? Should I allow direct contact between parties?