I think this article is emphasizing custom tags / code reuse as the primary feature of React, which isn't really the case? The whole reason React was a game changer was because it eliminated (as much as possible, anyway) the invisible extra state stored in the DOM from your app and made its rendering declarative, which greatly reduces how much state you have to keep in your head when reading and reasoning about your app UI logic.

Web components don't address this on their own, which is why a lot of libraries still exist that build on top of them.