I will first congratulate telegram and it's users for this new offer, but yet am not going to say it's a big catch for the bitcoin network considering that we are not sure of the coins thiw wallet could support, which i believe it's obviously not going to be all cryptocurrencies, even though there's no how they will start with the enlistment of supported currencies without mentioning bitcoin on their list, however using this wallet as a bitcoiner is not encouraged enough because it's no difference from an online wallet.

Secondly if we consider the rate at which telegram itself get hacked and leak user data, having a wallet with them is neither safe because if the user's contact number is attacked, it renders the wallet on that account being compromised as well, all these are nothing different from using a centralized exchange and has same level of risk which is not good enough for security and privacy.