My original paper on the system shows some more interesting examples, such as logical inference rules that can toggle between natural language and mathematical symbols: https://willcrichton.net/nota/

I'll be adding an "Examples" page with more interesting content soon.

The reason for using React is that it provides a nice model for components that encapsulate state and interactivity, so a user can just write "@Component{contents}" and the component author can deal with all the tricky UI issues. A design goal for Nota is to be as declarative as possible, while still integrating nicely with Javascript.