I think the reason the idea isn't more popular is because there isn't very much you can do with the results on our engines. The only tweak you can really do without affecting other things adversely (arguably) is maybe change the carbs jet up or down.
While it's fun to pull the choke and watch the sensor go very high, or turn the mixture screw, you can get similar results by just looking at your plugs. It IS pretty cool though!
