It is on the one hand a finisher for recource decks (there are only a few of them like ancient sage or bank), on the other hand it could be very usefull when you got a great hand, like a hand with a bunch of powerfull dragons.
If no facility = 1 then
Each resource production 15*(number of facility - 1)
Facilities = 1
I dont know, the "number of Facility" can be missread.