1x on a cyclocross bike is great...so much better than 2x, IMHO. It all has to do with dropping chains and simplicity when in a race or training for a race for me. 1x with a chain keeper up front pretty much ensures the chain won't come off when shouldering the bike, placing the bike back on the ground for a run, riding through muddy pitches while shifting. It's just way easier.
I would not like it for road. I never once had a problem with my Ultegra or etap front shifting on the road.