Desy, as Byeordie alluded to, I am a collector of GB's for all my cities. I have all 16 through PE in three of my 10 cities. I have one city with 10, one with 9, three more cities with 5, two cities with 6. I also have several of the quested buildings in all of those cities. I like to have buildings that can't just be bought with ingame coin or RL $$$. Whether they are worth the time and effort or not is beside the point. I won't destroy or delete them either, no matter how obsolete they become in the process of progressing through tech. It took much effort to get them on one city, when you multiply that by 10 cities, it is very time consuming as well. It's primarily the reason I no longer PVP (in addition to the sheer boredom of it). Since city score is of no consequence to me, I would rather focus my attention on the collection aspect of the game.
Even though it's horrible statistically, is an enormous waste of space and not even worth the time or resources to build. It's a Great Building so I will build it.