The friction comes from having to sign up for different forums or services. I'd wager fewer people use (or even like) Teams than Discord among the tech enthusiast types who are willing to give them feedback on their product.
I'm not even sure if there is a way to have a team/channel for external users that they don't need to be invited to (I know you can jump through hoops to make it so they don't need to be guests in your tenant at least) or that there should necessarily be something like that in the first place.