You can create a playlist of only the girls you want to see at a particular moment. This is especially very usful when you have a lot of cards.
It allows you to select group of girls depending on what you want to see without either having to activate or deactivate them individually.
As a very simple example, say you want to be able to play all girls in bikinis. You would highlight all the girls in Bikinis and then click save playlist. This then creates a file. When you load the file it will immediately activate all girls that you saved in the playlist and deactivate others. Of course you are then free to manually amend this playlist activate or deactivate girls in your collection as you seee fit.
You can make all sorts of different playlists mixing and matching girls as you like.