It’s true that a magneto contains several mechanical components. For instance, it has a rotating armature running between permanent magnets and contact breakers. However, this mechanism is self-contained and generates its own electricity.
A coil system, on the other hand, does not generate its own electricity. Instead, it must be supplied with electricity from the battery and, in turn, the alternator. A coil system is worthless without a supply of current. In the end, a coil system requires nearly as many bits to run as a magneto, especially when you include the necessary battery and alternator.
Electronic ignition systems have eclipsed both coil and magneto systems. These ignitions have fewer moving parts but have increased electronic complexity. Moreover, they are inelegant to look at, in my opinion. In contrast, a magneto hanging off the side of a Norton provides a cool old school racing look.
Rasputin's Revenge MC