I suffered through two or three to get a feel for them, bought a copy of McDowell's Cracking the Coding Interview and did a few exercises, reviewed some basic algorithms, and decided no more leetcode.
Having done all that, I figured out that the answers to leetcode questions always involve knowing the trick or hidden clue, then kind of laboriously grinding out the code.
It's a kind of gatekeeping while appearing to be merit-based, because knowing the tricks is like being in the right club. In fact, McDowell's blurb for his book says it right out: "Learn how to uncover the hints and hidden details in a question" [1]. Getting the answer doesn't depend on knowing how to do software development, it depends on being in the right circles to know and share the tricks.