EDIT: In fact, the puzzles in Zelda are so damn easy that I'd rebound the question and ask how anyone who plays the game specifically for that element could enjoy it.
Zelda is about environmental interacton; studying your surroundings, noticing patterns and posing questions like "
what happens if I..."
While swimming you come across a bridge and at this point most people assume it's a dead end so they turn around.
But
what happens if you decide swim up to it?
Discovering this secret area was mindblowing in and of itself, and talking to the NPC rewards you with a bottle i.e. a significant item that has a meaningful gameplay function.
Another thing that is unique to Zelda games is the deep level of interactivity with objects in the world; In OoT the main purpose of signposts is to read its contents, but
what happens if I slash it with my sword? I mean it looks kinda fragile... a-ha! it breaks in half! but not only that, the shape of the resulting wooden planks depend on which direction the sword was slahed in. Then Nintendo decided that wasn't enough, so they placed a signpost right in front of a pond and as a kid it made me think...
what happens if I cut this one? Well it turns out the developers went out of their way to program actual floating physics because yes, the plank actually floats on the water. In other words, the signpost you cut off with the sword interacts with the water in a way you don't expect to see in a video game.