277V What's the purpose of this lamp?

my guess would be retrofits like bypassing a ballast and wiring the socket up to 277V mains . or the remaining incandescent highbays in a factory

Ahh, the Mogul base! Thanks, Rick

These replaced the failed induction lamps in globe fixtures, we installed a mogul socket and used these directly to the 277volt line. The 2700K shown was the wrong color, sent by the distributer, we asked for 5000K to match the existing induction. The 2700K look Orange compared to the 5000K