I would be stupid not to admit that building on top of a platform is a risk. Before I had apps built on top of platforms and both times the platforms released my features as native experience (GitHub reviews, Twitter threads). Telepost needs future outside of Telegram ecosystem.
Messengers slowly replace social networks. Chats are everywhere, your bank support, practically every page on the internet, even on your wrist. You chat to get to your Airbnb, and you chat to get a ride to it.
Telegram made it evident that channels are one of the best ways to reach your audience. You get to your readers' inboxes directly, without messing with their faviorite social network sorting algorithm. You're not expected to write a paper, and you have more room than on Twitter at the same time. At last but not the least, Telegram is as personal as you can be to your reader: directly in the place where they chat with friends.
Also, people are got used to the snap chat experience and asynchronous nature of it, so they don't want to get back to old ways to do things.