It is all about how the designer approached what they wanted to do. The magnetic pickup is versatile and reliable and only a 2 wire set up. The box can condition the input signal, and in the end whether they use an PNP or NPN transistor determines whether it triggers off a rising voltage or a falling voltage. Those 50 year old systems still work fine from the distributor portion, even when left to the weather. Clean right up and work. Chrysler was first, other had the advantage of seeing what they did, then follow-up along with improvements that where occurring in the electronic field.
I agree as it makes sense. I worked for Chrysler from 1986 until 2011 and when they started changing over to fuel injection they started using pretty much all Hall Effect units on them for the crank and cam sensors which made me think its a cleaner signal with the instant switch of the digital on-off 5 volts compared to the magnetic pick-ups AC signal that generates its AC signal to positive and then negative. But the Hall Effect is a 3 wire unit with a signal , power and ground wires. Ron
