I feel that same way about AD/BC. If you are a Christian, or familiar with Christendom, then those terms make sense. If you aren't familiar with that religion, then you'd have to Google this "Christ" person to figure out that the dates have something to do with when some people claim he was born. Since Greek culture is heavily Christian it makes sense for you, but for someone in a non-Christian culture, they won't know what you are talking about. There's even some cultures on Earth that don't use the AD/CE-BC/BCE calendar at all. 

And yet the Skybox cards call their dates tera' DIS, as if they are used by the whole planet.

As children, most Americans have no idea what A.D. stands for, and some don't know what B.C. stands for. That doesn't stop them from saying AD and BC, though. CE and BCE are largely reserved for publications, and then only the more scholarly sorts. You don't need to know anything about Christ or Christianity to use AD or BC, or to use Christ as an epoch.

Keeping time is largely a matter of convention, not logic. You don't need to understand conventions to use them.

-- 
SuStel
http://trimboli.name