Telegram is a publishing platform. It's a big deal in the post-soviet countries. The "channels" thing is widely used for publishing by media, gov and bloggers. It's more like social network than plain messenger for a long time already.

I did similar rss-like implementation for my own needs because of frustration of reading and experience, also there is a bunch of similar services.

The reason for not using microblogging is engagement. No one will read it and no one comment on it. Telegram had built-in comments for channel post and people actively interacting here.

I'm somewhat popular blogger in my niche and so far telegram is the best channel I have. I repost all stuff to my own site and medium, but it gain a fraction of views and interactions I get on telegram.