Yes. My UI's functionality was what I would personally describe as "unbelievably complicated," but I don't know how I would have done it without the modularity of React. It's a full-blown sandbox for playing Magic: The Gathering. I'm sure it could be done otherwise, but React is what I know and it didn't make sense to me to work in something I didn't know rather than something I knew well.
Did you write it in react? This is really one of the use cases where React can become a hindrance.