I have several pages of an original GM manual supplement which discusses some of the objectives of their interference suppression schemes. Unfortunately the manual is packed away in storage awaiting our move in the spring. Some time in early summer I intend to scan this information and post it.
In these designs, engineers didn't necessarily take a "that's good enough " approach but tackled each individual aspect separately and also together. That is why some aspects seem so minor in relation to the overall picture. Often the objective in engineering isn't to just find the easiest solution but rather to create a design with the very best result, even if it has a very small impact on the over all picture.
On the subject of distributor condensers, I have seen it stated many times that it dissipates the energy created by the breaking points. The role of the condenser in the ignition is to create an LC circuit with the coil that oscillates at a high frequency and sustains a burst of coil AC voltage. The energy is dissipated by the resistance in the system including that of the coil. When running properly the system creates a high frequency burst with a fairly short decay time. By high frequency I mean relative to the points cycle.
