Concubine’s are seen as extensions of the emperor. Gender doesn’t matter, only status. And when you’re a concubine, only when you’re the favorite of all the emperor’s concubines you have even more rights than the others. Normal concubines get gifts and silks and foods and nice rooms. When you happen to be the favorite, you get power and anything you could ever want, along with staying at the emperor’s side, day and night, no matter what boring event they may be attending, or a sick day in bed.