With an open tagging system, you do not consult any descriptions. You just write in the tags you think would describe your game or should be associated with the game. It is tagging, not selecting categories like game or not game.
To elaborate.
The tagging comes first. Then comes the description what people use those tags for.
And that would also be the explanation why the 3d description is so vague. Or why you can propose a new description for a tag.