If you start from the premise of domed cities, then the expansion pattern pretty obviously says glassing in the entire moon is the natural end result of that. The lower-gravity drastically reduces your requirements, and the regolith can be fused into glass and moved a 100m up to form the roof.
It also reduces your energy requirements long term because you can use mirrors at the roof-level to reflect sunlight around the entire surface to avoid a 2-week night-time cycle, and adding an atmosphere means you "naturally" can keep it warm.
Since the pressure would be exerted outwards, the entire structure would be mostly self-supporting - requirements would lean towards figuring out how to repair it in the event of meteorite impacts, but self-sealing plastic layers could be developed.
Well, impacts. I suppose that a vertical hit at interplanetary speeds (or earth-orbit speeds, that high up) will leave a nicely clean hole, but think of the enormous cut made by something coming in on a trajectory that would slingshot close to the moon surface if the bubble wasn't there.
Sure, with technology indistinguishable from magic you could still do it, but i don't known if there would still be much incentive for building the bubble left in that case.
