Macrumours suggest it is used only after all other avenues have been explored.
Quite a few people say that, and they do
have a good reason- it very seldom makes any difference, those systems rarely give trouble!
It depends on your preferred approach to fault-finding. Some prefer to try the most likely things first, others prefer to try the easiest. And resetting the PRAM etc is dead easy
(At least, it is on later Macs, not sure about the G4)