Quote: "Clever design but probably will not be so retrofitting able"
I don't see why not, it could be wired up to anything like a standard plug.
Quote: "adding a large cost to the price tag of anything it gets put on..."
They're being sold for £25! Quite a lot for a plug (a normal plug is about £2) but that's probably because they are not very popular. I could see this being nice if you travel a lot. I like this image:

Yes, that is three folded plugs plugged into an adapter. Amazing that the whole array is barely larger than a single standard plug.
Quote: "I do not see this solving any immediate problems aside from storage"
That's the only problem it's trying to solve.

Formerly OBese87.