I will not be the one to say you do or do not need an electronic engine kill. Personally, I believe a correctly set up engine does not, and is no more or less gangerous than a glow engine that has never had similar means of cut off.

A choke servo is a very effective means of cutting off an engine. So is correctly setting up carb linkage and servo throws where the iodle trim lever has the ability to fully close the throttle plate. So ask yourself, do you need three different ways of cutting off the engine and or ignition on top of the externally mounted ignition swith? That makes four. How fast are you with your radio? By the time you ran through the first three any impending doom would have already occurred.

As an aside, I have yet to hear of a brand of electronic kill switch that hasn't failed, or generated considerable grief with electronic feedback or interfering with ignitions. My feelings are if someone is so terrified of flying gas they should remain flying glow. They don't use electronic kill switches there, and the stats are pretty clear. Glow fliers experience far more accidents per capita than gas flyers, usually caused by putting hands in propellers or driving planes into the pitts. The hand thing is dumb. The pitts situation simply means they should not have been off a buddy cord yet.

Utimateley it's your call.