I mean, think about it. Why did the first Gym Leader we encountered in Mango only used Steelix? Six of them, even.

[ it's totally a gimmick because the mods know no mercy u_u ]

Puzzles are pretty challenges in Pokemon, actually. It can be as simple as finding remotes to open a series of doors leading up to the Gym Leader, or as complicated as sliding across icy floors to destroy massive snowballs that get in your way. Also you have to fight various Trainers along the way, so it can be pretty annoying.

[ war flashbacks to candice's gym ]