ohohoh do you have a link?
the problem is that the said "blockchain" should be able to link multisig and release coins for the wallet automatically once the trade is matched and not some kind of scam to pump a shitclone... otherwise they will not be chain neutral...
The ideal would be a Local Bitcoins version that could be stored in a P2P format. In this way, there would be no worrying about the site going down, hacker attacks and regulatory headaches like KYC. Also, there would be fees only for the transfers (mining fees). You would have a SPV-like wallet for each coin, pegged to this blockchain, and after synching, you would be able to trade each coin, and made deposits in fiat in the same way you can do in Local Bitcoins.