We have already Decentral exchange system. Called night trader.
And what is the volume of "night trader"?
All of these "decentralized exchanges" including BitShares are basically Ghost Towns.
The only decentralized exchange with meaningful volume in NXT...
With total daily volume of about $20-30,000 USD at 375 trades/day and growing...
With about 20 assets that can be considered liquid (and many listed on Polo and BTER)...
Plus it all works reliably, error-free and user friendly.
https://nxtblocks.info/#section/assets_exchangeWhen the Monetary System comes on stream in a few weeks...
Anyone will be able to launch an Alt Coin on the NXT blockchain... and volume will explode.