I think you are envisioning mandatory participation enforcement (which I guess would be a risk). You don't have to be in the channel all day - it's just there when you want it. I'd see it as more like having a desk next to your teammates. You can keep to yourself and not talk to anybody all day if you want (not join the audio channel), you can walk away from your desk cluster when you have something else to focus on, etc. But when you have a quick question you can pop into a channel and ask it rather than having to start a meeting or write out a comment