This is a nice project. The availability of goods being purchased directly by using cryptocurrency is another milestone for Bitcoin and other Altcoins. The platform is not so unique since it is similar to ebay or amazon but what makes it best for both parties is that it is a secured transaction since it is using block chain technology. The set-up makes it favorable for both the buyer and the seller since it uses smart contracts, runs on blockchain and you can maintain your anonymity and privacy in making a transaction.
The platform of Fair Ninja is not anymore new to anyone here. As what you have said, it is similar to eBay and Amazon because these two giant techs provide an online marketplace where any can transact and transfer immediately. But because of blockchain technology, Fair Ninja takes the advantage to them. Buyer and Seller might turn to Fair Ninja because they can seek trust in this project due to the decentralisation.