This appears to just be a contrived example implementing a familiar component to give you an idea of how React works. Of course, in practice, you just use a select when you want a select.
I find this often isn't the case unless, say, the dev comes from an Angular background (who is more likely to structure code in a top-down fashion, rather than React's recommended bottom-up components-first structure). I've seen a certain tendency to overcomponentize upfront (because hey, "Thinking in React" says to make a lot of very small components), and then see the components gradually grow in configurability over time, exposing more and more ad-hoc props for whatever "configuration" is needed at the time.
