Having both I can tell you there is a difference when using the Jscan vs the switch. The switch still allows the jeep to pull the power and throttle from you where Jscan shuts everything off. I was out in Pink Coral sand dunes when I was testing between the two. The jeep was not cutting the throttle with Jscan and was still cutting the throttle with the switch off. We tested on 3 jeeps that had the switch and jscan and everyone felt Jscan worked better then the switch.
From my understanding and I could be wrong, the switch just stops the modules from talking to each other but are still working independently. The Jscan turns the modules off so there is no communication at all.