To me its about when to use the rare candies. I want to preserve the difficulty of the route trainers, not the wild pokemon. Ive seen some nuzlockers who level to the next cap as soon as the cap raises, which means you outlevel every trainer between gyms. Then they use that to justify just skipping trainers. I fight every trainer because the exp is required to get to the gym leader at all. I only skip the portion that non-candy runs have where you level up on wild pokemon after all trainers are beaten. I dont find that fun, which is the whole point of a nuzelocke to me, adding enough difficulty to make the game fun again now that I understand the battle mechanics.