I think a good developer is composed of many things, and LeetCode/HackerRank type learning can help you become better at only a small subset of those things.
It's like trying to get your body into good shape, you need to work on different parts of the body, not just focus on your left arm (unless your left arm is especially weak and you want to focus on that).
It's like trying to get your body into good shape, you need to work on different parts of the body, not just focus on your left arm (unless your left arm is especially weak and you want to focus on that).