But you can no longer trust Telegram that things you had in your chat will still be there tomorrow. This feature feels like someone has hacked into your device and deleted files they didn't like.
Of course, I have nothing against being able to delete your own messages for both. A time limit within which you can do that is nice but I can live without one. But Telegram lets you delete every message in any PM conversation, including incoming ones, for both people. Or even the entire conversation, and make it disappear from the other person's list without a trace.