In the airline forums, there is some excitement whenever a new amenity kit is introduced. To be clear, I mean the bag, not the contents.

Because of the labels (Tumi, for example) I suppose that they're meant to be saved and reused, but for what? If I need a little pouch or bag that size for travel, the one from the amenity kit is bulkier and heavier than a mesh or light fabric bag, and if look and feel don't matter, there is something called a Ziploc bag. The only one I've ever found a good way to reuse was from SAS, in their version of PE, and it was meant to double as a shoe bag.