All of the decentralized exchange have a coin or intermediate point. (e.g . Next has nxt token etc ) and so applies for other current decentralized implementation. A decentralized marketplace has to be network dependent for its functions and not dependent of coin / token for its functions.  The Proposed Decentralized exchange is network dependent for its functions.

Basic Functions of exchange are -

Order books - Open / executed order.
Rate determination.

Getting order / price determining mechanism over the network would mean making a different ecosystem altogether.