The React aspects are really minimal, all the animation logic is by outside of React. We're really just using it for the jsx syntax to make it easier to return markup-looking components.
I get you, jsx is the most useful part about React. However, there is nanojsx now, which would be great to for mobile. React tend to push out large bundles. For example, MatterMost, it is great open source initiative, but the React front end often lags it quite a bit on older computers.