>>57875908Semi-legit anwer:
Was she important to the game doing well or selling well or any of that? No. She didn't show up in the anime (and was the first time that even happened for a female MC, even Kris was in the special eps) so they didn't lean on her for sales.
But, she was the new Pokegirl at a time when porn was taking off overall. Yeah there had been plenty prior, but there is a notable uptick in R34 porn and porn acceptance in various corners near the same period. Artists who generally only did SFW because it had been acceptable started dabbling in NSFW more publicly. It probably did start a bit more in Dawn's era, but Hilda was introduced after the swing and had the ass animation to give her a notable bump.