Who each one reaches
A channel post goes to everyone subscribed to your channel. A bot broadcast goes to everyone who has started your bot and has not blocked it. The two lists overlap, but they are rarely the same. Customers often order through a bot without ever joining the channel, and channel readers may never have opened the bot.
What a channel post is good for
Channels are built for publishing. Posts stay in the channel, new subscribers can scroll back through them, and anyone can share a post with a friend. That makes a channel the right place for news, new collections, articles and anything you want people to find later. A channel is also easy to join from a link, which makes it the better tool for growing an audience.
What a bot broadcast is good for
A bot message arrives in a private chat, next to the person's conversation with your shop. It feels personal and gets noticed. That suits messages for people who have a relationship with you: a restock of something they bought, a change to delivery, an offer for existing customers. A bot broadcast can also target a part of the audience, such as new users or a tagged group, instead of everyone.
The limits of each
A channel cannot reach people who did not subscribe. A bot cannot reach anyone who never pressed Start, and it cannot message people first. Bots are also expected to send less often: a private chat that receives too many promotions gets blocked, and a blocked bot cannot reach that person again.
Using both
The common setup is simple. Publish news in the channel, and put a button in each post that opens your shop in the bot. Use bot broadcasts sparingly, for messages that matter to customers. In BotLaunch the scheduler can time channel posts, and the broadcast module, part of the Pro plan at $39 a month, sends bot messages to the audience you choose.