I mean it how I wrote it. It would be nice as a creator to give certain aspects of being a GM to other trusted players without making them a full on GM. One of the biggest aspects I can think of is allowing a Bard to control the Jukebox if he has music to play as if his character were playing the song but not allowing him full access to all the GM tools such as maps and hidden stuff. Also if there was a semi-GM in charge of making town NPCs that you don't want to share with them the dungeons you have planned out would be another example.