Fuse technology has improved significantly since these cars were designed but they can still fail at a much lower current than they are designed to open or quickly open on current spikes. An open or tripped fuse/circuit breaker used in this application means an engine stall if the car is in motion or a no start/dead in the water condition, a mission critical circuit application, same reason ignition 1 (ignition system) is not fuse protected. Fusible links tend to be more dependable (if its connections are maintained and not abused) and they react slower to the occasional current spikes in this stock charging system. There is a reason they were used there originally and it was not because it was cheaper.