I was doing some research into RPM governors for diesel engines and could essentially find two different approaches. One was based on some NE555 based PWM circuit that based on the input RPM from a hall sensor creates more or less current in a solenoid that will actuate the throttle of the engine. It was usually rather complicated circuits with a lot of elements.
On the other hand I also found quite a few approaches where an arduino was used that took the signal from the hall sensor and essentially controls a servo that increases or decreases the throttle. It ended up being pretty much "Take arduino X, connect hall sensor to pin Y, servo to pins XYZ and run this code".
Objectively this is much simpler than a circuit with roughly 30 elements. So I was wondering, are there any downsides of using a "digital" approach for an RPM governance device compared to the purely "analog" version with just ICs and some RC components? Or is just about costs?