My understanding is
Power = speed x strength. Therefore if you increase one power should improve, but why wouldn't you want to improve both?
Gym components could be lift 30%1RM for reps as fast as poosible (it has advantages and disadvantageds) or
Lift 80-90% as fast as possible (it has different advantages and disadvantages than the one above)
Plyometrics – works the stretch shortening cycle of movement, whereas weights doesn't
I think it is up to the coach to decide, I tend to use the former weights and some plyo work.