I think you're missing the point. Bots now use ML and other forms of weak A.I. Facebook is building something closer to artificial general intelligence with Facebook M. The early forms of bots we'll see will do basic tasks but in the future they'll be as smart or smarter than us. This is a great long term play Durov took by incentivizing bot developers. Besides, Telegram doesn't have the same scale as Facebook (FB Messenger) and Microsoft (Skype) so they sorta need to do this to remain competitive in their hyper competitive market.

If I had any gripes about Telegram it's their lack of audio and video calling but I'm not going to complain about an excellent free product.