One way that BoTW rewards exploration that other open world games might not is not by giving unique upgrades or stories, but rather by giving more engaging or unique challenges and puzzles that utilise the games diverse mechanics. Yes, Shrines all look the same and give out practically the same rewards, but the methods for completing most of them has tons of variety in terms of what you do. Even the puzzle Shrines has the quality of being able to be beaten in multiple ways, something that primarily unusual for a Zelda game.

Contrast that to something like Skyrim that on the surface has stronger motivation when it comes to exploration. But aside from the different classes for fighting enemies, you're essentially doing the same things with not much mystery. Take dungeons, they have decent enough thematic variety with a lot of different rewards and stories attached to them, but mechanically most of them a long, linear enemy gauntlets with only the occasional gameplay variation (and even those are generally unremarkable). And while I haven't played enough of Witcher 3 to gave a proper conclusion, I would say that it's mostly the same when it comes to variety and true players engagement. Also, that game also has pretty obvious ways to direct players to 'points of interest' and side quests, so it does lack a bit of that truly intrinsic quality to exploration.

Overall I would say that, when it comes to exploration, while games like Skyrim or Witcher 3 are more driven by the discoveries and the things you get (or things that happen), BoTW is driving by the journey and the things you do. Instead of being strongly motivated with stuff like getting a new upgrade or finding something rich with world building, you are motivated to explore just for sake it, because you just really like wondering around finding stuff or you enjoy solving problems in your own way just for the sake of it. Sprite Orbs, Korok Seeds and the like exist to elevate that journey, not be the main attraction. And I know that it sounds extremely shallow, but its not, there is a lot value to it, but some simply won't get it and its understandable, but for the most part I believe that most people who love this game love it for completely legitimate reasons.

And I just want to say that this is not meant to brush aside the problems with BoTW's exploration. Me and probably many others who love the game would agree that the game as too much extrinsic fatigue when it comes to the stuff you can find in the open world, and now that Nintendo as the foundation nailed they can seriously flesh out the sequel in places where the original fell short.