That condenser (capacitor) likely reduces the arc at the points that would energize the coil again, curbing spark. In electronic ignitions I build, no capacitor, just a IGBT. The IGBT does have a small amount of drain to source capacitance. The IGBT is a good switch. It also has avalanche protection that limits IGBT drain to source voltage to 390V. The strike voltage can be estimated by multiplying the coil - by the coil turn ratio, typically 75 or 100. The plug gap and other dynamic factors including compression, changes the strike voltage at plug.