I think we got a little off the initial question.
The Extension messages sent with the chat endpoint are not sent on the IRC channel directly but with another “technology” (I don’t know the specific) that is listened by the website. Why? I think only someone from the Twitch team would be able to answer. It might be linked to username, might be to allow interactive chat messages later (mentioned in the roadmap), etc.
If we really want to send messages to a specific chat, we have to connect a chatbot ourself for now. Things might change in the future but that’s how it is now. You could build your chatbot to just connect to the channel, send the message and leave for example so you don’t have to handle all the incoming messages (just a theoretical idea here)
As part of "sending notifications to the streamers it is quite complex, because every extension requires different things. For example in my extension if the streamer doesn’t answer to the notification in 10 minutes it just goes to expired so I get that problem too.
And honestly I think that we have to ask the streamers and be honest with what we can do technically and see what they want and what they can do on their side because what I see is just “my users said that”. I might have a different approach since extension are side projects for me and I use them to experiment.
We will need a talk about that but not without asking the streamers first. And instead of just “complaining” we could try to find some ideas to improve the dashboard too (And I know a lot about complaining, I’m French).