Parmandur
Book-Friend
Yeah, based on a bunch of other stuff, one rather suspects that Beyond is going to be turned into a marketplace soon. That is an unstated piece of information that makes sense of a lot of this.Note that Steam charges 30 percent to sell stuff on there. However, the products are directly uploaded on Steam's servers, people buy it on Steam, and then Steam sends the other 70 percent back to the devopler.
WOTC wanted 15 percent in exchange for some advertising. If a person saw a 3PP product on D&D Beyond, they would have to then buy it somewhere else. That would be a step too far for many. Assuming of course the people on D&D Beyond arn't those "3PP is gross" types.