Bungie is simply trying to keep player population up. Last week there was nothing at all to play in the game, with the corrupted as nightfall and most non noob collectors already long done with the solstice bullshit, so the only way to keep some level of activity was the GM playlist. This week there was the trash exotic that all jobless PR agents filling up Reddit and the like with false info baited players with, banner and the GM is only 30min long so it gives good alternatives to incentivize players. Next week they double the loots on the LOS... So just wait for the week after or so when there’ll be nothing at all on the agenda to see the playlist back. That said completing all GM is a piece of cake, as long as you don’t follow stupid online guides. In fact, imho and experience the trick to complete them all fast is to have a player running banner shield with Ursa Furiosa.