2 channel vs headphones

Yep. The only way to go for early morning listening while wife is still asleep.

I mainly use headphones when others are sleeping in the the house or when traveling.

Not if I can help it.

Yes, separates speaker system (see virtual system), open cans with dedicate HP amp (Dan Clark Ether 2 with Woo WA6SE with upgraded tubes), and IEMs with dongle DAC for on the road (Westone Mach80 with Dragonfly cobalt). 

I mainly use headphones when I'm moving around, either in the house or outside.  I miss the depth effects that 2-speaker systems provide, even though my headphones/earbuds can hint at those effects.

I also use earbuds when I'm recording, mixing and mastering my own original music.  I do a check with my main speakers before final mastering, mostly to make sure the instruments are panned the way I want them--speakers give a different perspective on that than headphones.