In case you weren't around for the Big Controversy (TM) of the late "aughts," a minority of dweebs attempted to introduce BCE/CE as an alternative to BC/AD, because numbering systems are
obviously the most pressing issue in modern religious conflict.
Most people, appropriately, didn't give a shit because the concept was dumb and "common era" was simultaneously meaningless and hypocritical.
Nowadays 90% of the time the former units are used it's to make an impotent political statement (i.e. the exact sort of thing "fedora atheists" thrive on)
EDIT: Hah, I didn't realize you were the game's dev! Makes it even more baffling that you would use "CE" when the characters you're writing about were themselves Christian converts who would have, of course, dated everything as AD