I'll bet it's because the bag gets warm when she lays on it and makes such interesting rustly sounds. I would advise caution, though, My daughter's cat became entangled in the handles of a plastic grocery bag and it had to be cut off her. As long as your kitty isn't chewing on the bags, I see no harm in what she's doing, You may want to cut the handles of the bag so she can't get entangled in them.

Izadore (Izzie) answered on 10/13/12. Helpful? / 0