It's fairly common in the USA to have 480 phase to phase, and 277 from one phase to a neutral. There's usually a stepdown transformer to provide some 120/208 but then again, many things CAN run off 277/480. In commercial buildings that is.
Incorrect.
In the US, 480V service is the start of what is usually called "heavy power" and usually only available to industrial areas and large commercial developments such as malls and office buildings. In large buildings it runs HVAC and is also distributed throughout the building to feed local 120/208V transformers that feed power to different areas of a building.
The only common use for the direct 277V phase-to-neutral is for overhead lighting fixtures designed to accept the high line. The 3-phase of course supplies large 3-phase loads. For all virtually all other '200V' devices, they usually top out at a maximum input of 240V and WILL quickly fail when fed anything over 250V.