I read an interesting viewpoint on this from a bodybuilding standpoint. A guy for years was always doing 8 to 10 reps with legs. He decided to try really high reps. If my memory serves me he started with four sets of something ridiculous like 40 or 50 reps in the leg press. He said his leg showed quick growth and vascularity. He grew weary of the high reps and he went down to something like 20 reps. He kept his gains and improved even more. He explained it as he felt he built better blood pathways through getting a huge pump.
Since I train with low sets when I briefly tried feeder sets that was a long thread on the Gossip section. My arms really responded. Maybe the pump was was I needed. Since I care about being strong instead of pumping light weight I soon dropped the pump sets. I really believe in the value of the pump. I now end my bicep routine with two sets of 20 reps and the arms really respond to it.
In the end from a bodybuilding standpoint the muscle grows best from both strength training and pump training. They go together.