Thinking about things in isolation, you will not see the benifits of streams. UI state is rarely simple unless you aremaking a CRUD app; then of course this will feel overkill.

The power of streams comes through composition. Abstraction of threading is another powerful tool in the concurrent world. Less important on the client these days but becomming more relvant with web workers. Watch your code turn to spaggitti very quickly without this abstraction!

This approach could definately be considered a pure approach to the problem. If u are a familiar Rx and simply want to take bite sized chunks streams and start using them in your app, i recommend converting yours events to streams (fromEventPattern) then composing them together. You can do this with your traditional Angular/Jquery app. Once you start to come come around to the benifits — ie. implementing a auto-complete text box that maintains a maximum amount of server requests, and delay on triggering requests, with a single line of composition — you start to the power over imperitive code.

In the C# world, we had ReactiveUI for quite a while, which coupled nicely with the MVVM pattern.

I came across cycleJS while looking at creating a DDD/Event sources UI. I came across react and the flux pattern which just looked like rebranded ES to me. I was looking for someone using Rx with this archtecture, because i got hooked on in many years ago. Glad to see some people thinking outside the square!