FBO Systems

They don't make an Ignitor 3 for an electronic distributor for one.
So in order to run one without having to do your own fabricating to install it you have to put it in a points distributor.

For two, the pickup system using a points cam as the trigger unit isn't very accurate.
It varies a little due to the rise and fall of the cam surface instead of using a vane for a sharp signal point.