@nathan-rokus well in that case they have to do that via another platform than youtube because they only support the channels of the big boys now.

They do this more often to beta-test a feature and see how it is going before rolling it out to more users. Also, the big users will most likely get the largest amount of contributions so from an investment point of view it makes sense.

They will probably roll it out to users with at least 1K subs in the future :)
However below that they won't because they want to verify the content is legit before granting specific options to channels. (in general that is).