Arched bridges? Arched cathedral ceilings? Dome ceilings?
With the increased structural strength of arches, we could create much larger rooms, without pillars - map rooms where you can easily walk around the map perimeter.
In addition to the increased pillar-less room size, you could have two types of arches: Foundations that are arched underneath, but flat on top, allowing for more foundations on top of those and ceiling ones that are arched under and round on top. No building on those.