Why choose 120 volts?

[Seth Mattinen <sethm () rollernet us>]

I have a pure curiosity question for the NANOG crowd here. If you run
your facility/datacenter/cage/rack on 120 volts, why?

I've been running my facility at 208 for years because I can get away
with lower amperage circuits. I'm curious about the reasons for using
high-amp 120 volt circuits to drive racks of equipment instead of
low-amp 208 or 240 volt circuits.

~Seth