There are several advantages: the voltage rise rate of the spark from a stick coil is faster than from a remote coil because the high tension (spark plug) wire acts as a capacitor. There is no voltage loss in the secondary, high voltage, side of the ignition because there are no wires and no wire joints between the coil and the spark plug. The weakest component in ignition system secondaries, the spark plug wires, are eliminated thereby eliminating a potential (and realistic) failure point. There is much less high voltage 'spray' flying around the engine compartment and the vehicle in general making far less interference for electronic devices in general and radios specifically. 'Coil on plug' systems are virtually impervious to water.
The move to 'coil on plug' system is the result of a series of steps in the evolution of spark ignition and the most current system being used. Before COP systems, there were individual coils for pairs of cylinders used for years just to remove the rotating parts of the ignition system, and that in itself was a tremendous improvement in the reliability and function of ignition systems.
Finally, it compliments KiPass nicely. Well, not really but it was an opportunity to use the word 'KiPass' Sort of like how you can get the words 'when suddenly' into any sentence in the English language....'I was typing a response to your post 'when suddenly' I thought I could mention KiPass'.
Brian
The holes would have to be big enough to get a grip on the stick coils. Somebody please tell what is the advantage of having stick coils.