I think that's a great idea. I mean reputation a rating system attached to your npub. If you screw someone you can start at zero, but anyone at zero had nothing positive going for them either.
Discussion
I'm honestly not sure how exactly it would work, I just know other options for trading BTC peer to peer can be intimidating.
Maybe a dedicated relay or set of relays that exist solely to match buyers and sellers as well as provide escrow services (that could be another way of addressing the trust problem with purely P2P trades).