Not project or platform is perfect in security.

Telegram has different layers of security: Login with your phone number and login code; a security password (if you set it up for your account security). You can recover your security password via email if you forget it. Your email should be secured well with its password and 2FA protection.

I think it is good enough to use but I don't like to trade via Telegram especially if it is on my phone. On computer, the problem is trading volume like we have many centralized exchanges and decentralized exchanges, we have to choose best to use. I am unsure that Telegram trading platform can be attractive enough in trading volume, liquidity etc.