Definitely the most simple yet genius development so far.
How Wrappedkitties work is you will have to send Cryptokitties to the Wrappedkitties smart contract in return for a WCK Token, then for each WCK Token you can then swap it again into another Cryptokitties.
My guess would be the market will be filled with tons of unwanted kitties, because no one would be dumb enough to swap away precious kitties such as fancies or exclusives.
Its basically giving a kitty for a kitty. They do include a feature of bundling multiple kitties in one transaction to save gas fees. Really loving this feature as the p2p trading platform for Cryptokitties.