What does this thing do, that a plastic...
What does this thing do, that a plastic (or paper) shopping bag from the local grocery store can't do?
1. Zip shut.
2. Pack into a rectangular, box shape.
3. Costs a lot more
4. When you get to your destination you will be far less likely to fill it with some trash and chuck it in the nearest bin and just buy a few things at a local store and replace the one you just chucked.