The advantage with 277 is in simplified lighting circuits.
If the facility has 480V 3Ph, you take each leg and neutral and split up the load among L1 L2 L3 to balance the lighting fixtures.
It makes a difference in things like schools, factories, and large stores.
Beats using iron to get it down to 120V.
73DG
This, right here.
You design a 20 amp circuit to be loaded to 16 amps.
You get LOTS more lights on a 277 16A circuit than you will on a 120 16A circuit.
Which translates into a lot less wire, a lot less conduit, a smaller panel with less breakers, less time paying me to land all that additional wire in a panel.
277 is just a lot more economical when you have it.
--Shane
WP2ASS / ex KD6VXI