Retained accy power keeps the radio and the windows powered up after you take the key out of the ignition.
Only GM's,some Nissan's(that still use keys),and a much newer Ford's and Chrysler's have that,otherwise you must turn the key back one notch for ACC power.
I kill 2-3 batteries a week because of that stupid feature at work since I always have the drivers window rolled down and reach through to turn on/off the ignition totally forgetting I have to open then close the door for the ACC power to shut off.
Can't tell you how many GM,toyota,honda,and nissan inner door handles I've broken since they can't open the door from the inside if the door is locked.Major safety hazard,I can understand rear doors but not front doors.