Its GM delta. Why it is put everything, is beyond stupid. Playing -40 is not fun time playing. Bungie, look at player numbers and start doing opposit of what you are doing now. Numbers more likely will go up then.
10% of the player population will say...
1) -40 delta is just too easy, you're dog poo and should -blam!-
2) Bungie should ban anyone who can't solo -60 delta dungeons and raids
Bungie 100% caters to the top 10% and the content will continue to be made specifically for them and them alone. The top 10% thinks you should Facebook live yourself for even logging into the game that actually belongs to them.