Even more important than appealing to new consumers is appealing to new producers. Everyone who occupies some app-space or topic-space or activity-space is showing newer arrivals that These Are Things You Can Do Here.
It's like a live advertisement of the possibilities, and they can then ask the People Already Doing This how to best go about joining in.
So newer streamers and can ask Grinder how to get started and which apps are best and etc. The barrier to information is much lower when speaking to colleagues, than when speaking to the app developer or just shouting into the void. Besides, sometimes the app developers aren't actually heavy users of that particular app. They built it for other people to use and those other people are Power Users and they're actually the usability experts on the app.