They do if you do GE past level 1.
oh Stephen, always looking for a contrary position, I think you've been around the forum long enough to know the issue but can't help yourself to try to argue some "opposite" position that really needs no argument. Yes, okay, if you don't have an Arc already by the time you reach AF, which most players will, and you play GE then yes Observatory and Atomium can have value as they will cover the costs of GE.
OF unlock costs are 180 OF goods per week. If you collect daily this is the level you need;
Atomium Level 1
The Arc Level 1
Observatory Level 2
Okay, so sure, you don't want extra forgepoints in your inventory then you can forgo getting The Arc. And if then your only concern is paying your current age GE costs through one of the remaining GB's then Observatory is recommended as it has the smallest footprint. However perhaps you've had a hard time getting prints for the Observatory by the time you reach AF, well then that just leaves you the choice between Atomium and The Arc providing of course you have the prints and goods for either. So I suppose then if you value the Happiness over the forgepoints in your inventory then the only choice is Atomium unless of course you have Special Buildings that you can get the goods from then I guess you don't need any of these GB's and you can just put the goods in the guild treasury manually.
I don't know Stephen, should we account for every playstyle in the game just in case?
Let's see, perhaps you have 20 OF players in your guild all with level 100 Arcs, maybe they're like, hey, we got 100,000,000 OF goods in the guild treasury that don't go anywhere but for GE costs, maybe we can give that OF player a break who doesn't have any of the Guild Goods GB's. I suppose then in this scenario the GB's have no value for that person.
Hmmm, well, perhaps you're solo guilding and you reach AF, no AF goods in the treasury, want to plan for the future because you know when going into OF and unlock GE you'll need AF goods, so best to stock up as much as possible, go ahead then and get all three GB's and level and collect daily as I'm sure they'll be of value in that scenario.
I don't know, can we think of more? Maybe you are not in and don't want to be in a guild, don't care about forgepoints in inventory and like to make the citizens angry, in which case ignore these GB's, they have no value to you.