What exactly is new that doesn't exist in the existing marketplace? Multi-sing wallet? It's just the same as Fiverr. Because multi-sign wallet means you must sign the transaction if the buyer refuses to do. So here is come censorship, you have to investigate who did the fault. It's the same on Fiverr if the buyer has no dispute then the fund will be released to the seller. If buyers dispute then they investigate it manually and decide what to do. If you need to prevent fraud there is no alternative to censorship. So ultimately the marketplace just likes the same existing centralized platforms. Just a multi-sign wallet wouldn't make if difference.