Gravel, although for commuting I'd ensure I had rack eyelets and consider longer chain stays for pannier heel clearance.
A drop bar bike will be more aerodynamic (the bars are narrower even if you don't sit lower) and comfortable on road rides, and you can get faster tires in 700C.
The double gravel bike you're looking will have much more appropriate gearing for road riding, especially if you run a smaller cassette. Many if not most road riders don't like a two tooth cog gap until the 17=19 spread and a few of us like an 18 in the middle there. A single chain ring is not conducive to running a crank like that.
Last edited by Drew Eckhardt; 08-18-19 at 04:19 PM.