What may take you more than a month to get 50 FGs is cut by more than half in DMM due to how often DMM give "freebies"(by that I mean FGs).

You don't get "Gem Starvation" status all the time in DMM. For special occasions, you will get free FGs in dailies for almost every month. You don't get this from Nutaku.

For example, reach 100 users for playing FKG,
DMM: Gives out 1 FG for every login until certain date
Nutaku: ...LOL :P

And you wonder why some users prefer DMM more.

Sure, it doesn't increase chances to get 6* girls but people love the generosity more so. And that generosity allows us to draw Gacha more often without spending money on unnecessary deals(lets people control their impulsive spending).