MMORPG's work because they create a community and because they offer constantly updated content. I can't see either of those working very well in a FPS.
I don't see why a FPS cannot create a community and offer constantly updated content. Its literally only a matter of perspective (First Person, 3rd Person, etc).
I've been working on Cash-driven Skill based Game concepts for over 2 years now. This was the original premise behind Tournamentblitz.com. I've have revamp TB's design several times to support in-game cash transactions for real-world and virtual merchandise, advertisements, and several other Cash Tournaments models such as Scavenger Hunt and Treasure Hunt.
Making money in games is not new. I know 3 individuals who have made money $100-$800, selling characters they developed in MMORPGs. So to claim its a 'Groundbreaking' FPS demands I LOL. Kwari is only stepping on a pebble of possibility. If they dont offer fresh content, the lure of making cash will lose its zeal...quickly.