Absolutely correct.

What you need is a positive way of cutting the ignition and stopping the engine, right now. Full choke is not the solution.

When we all got started with the giant scale activity with the formation of IMAA, several decades ago, this was not even a question. Any plane at any event without a positive ignition kill did not fly. Now there are lots of people getting involved who do not have a good grasp of fundamental issues and requirements. Some have absolutely no way of stopping their engines, whether gas or glow.

Bottom line: Is the opto kill switch worth the extra cost and effort for installation? You bet your ass it is.