From an incentive standpoint, those kinds of people are the ones who'd be most interested in a marketplace that can't be shut down. Lower fees aren't the killer feature that many hope for, as eBay's high fees go with its huge network effect plus "Trust and Safety." The sad fact is, a lot of eBay clones have been launched and virtually all of them have failed for the same reason: no buyers to speak of. Sad but true.
eBay does add value in the form of a moderation service. Generally it favours the buyer, so you can buy with some confidence that you will get what you paid for, or your money back. That's important. Even the Silk Road was moderated, I gather (I never used it myself). The Nxt marketplace has nothing like that. It doesn't even have a formal reputation system. I'm not even sure if phased transactions help with third-party escrow. So it's far from a complete marketplace solution.