By the same logic, you can argue that the same percentage of players have been raised to orient their sense of time with years ticking up and not down. Thus, for gameplay purposes presenting the year in BC as opposed to AUC would be one hell of confusion for them.
What you meant to say is that presenting the year in BC could be more useful from an immersion purposes, kind of, because they can compare it to our history. Although it seems to be much less close to history than HoI4 and even EU4 do, because many important countries are still relatively small, there are a lot of them and they don't like to blob but like to explode, based on the few AI timelapses we already have on youtube.
lolwut. People are accustomed to the dating system, not to the absolute values of integers increasing. That's like saying people flying in orbit around a planet shouldn't feel strange when 'falling' upside down or sideways, because by the same 'logic' they should be used to the laws of gravitational attraction.