Well I'm actually more interested in a marketplace for certain types of *labor* of the variety where the tasks are highly commoditized, repeatable, legible, predictable, and most importantly, discretizable -- if you have a series of labor transactions where you need each thing to work such as paying a developer to build an app, there is risk at the size of the entire project, but for a delivery of a physical item, risk is bounded, acceptable, and low enough that it can more easily be overcome through costliness of breech of contract.

Why not http? Nostr is better for real time, dynamic interactions that combine encrypted DMs, the critical relational aspect that allows trust, easy payment integration, and mutability resistant and Sybil resistant transaction history. Also eliminates single point of failure.