It's used but some of the core gnome developers have advocated for people to stop using it.
What I can find with a quick search this morning: [1] [2]
Then again, there are also several people who still say it's worth using: [3] [4]
So maybe it's just Emmanuele Bassi advocating against it. If you look at the development pace, though, it hasn't really seen any significant development for quite a long time.