From the looks of it All City markets the Zig Zag as a road+ sort of bike, maybe not fully a gravel machine? Tire clearance is narrower than what most folks would consider technically gravel size: https://allcitycycles.com/bikes/zig_zag_ultegra
I use one of All City's lower-end 612 chromoly tubing bikes as my commuter and it's great for that. Quite a bit heavy and stiff though. Have to guess that their ACE, Columbus, or Reynolds -based frames are much better for proper gravel riding as I wouldn't personally recommend the 612-tube bikes.