Probably more about timing. The AC impedance is measured at 1kHz (I might have a bit more about this at a later time).
Generally AC impedance is smaller than DC resistance. AC impedance is very interesting for both fast pwm and boost/buck drivers (But they uses a much higher frequency).
The DC resistance is more interesting for how the battery handles high loads over a couple of seconds.
Both will increase with age and can be used to get rid of weak batteries.