I love rxjs but I wouldn't call it user friendly. It's essentially a text encoding of data flow programming and requires a totally different mental model to react. The explicit coding of time is great, but for most reactive js code react's own logic is simpler and more idiomatic.
For sure, dont mean to argue that point at all. I'm just saying the interface of swiftui is very much observables + a react like component setup, its pretty neat to see something like that coming from Apple