I find that small apps tend to turn into big apps over time, and Flux lets us build with the confidence that, as new features are developed, our apps won't have to be deeply rewritten. New, unexpected features tend to fall into place with Flux, with a minimum of effort. I have seen this time and time again in working with Flux.
The Dispatcher is not an event queue system, but rather a registry of callbacks. This is a significant difference. The callbacks may be invoked in a specific order, synchronously, so that dependencies between Stores are managed effectively. Stores declare their own dependencies -- the Dispatcher knows nothing of the internals of Stores -- through the use of the dispatcher's waitFor() method.
Yes, you don't absolutely need the ActionCreator helper methods. You could call AppDispatcher.handleViewAction() or even AppDispatcher.dispatch() directly in the View. But keeping these things separated out keeps the code nicely organized and keeps application logic out of the View. Additionally, I find it helps to maintain a mental model where the only way into the data flow is through the creation of an action, codified in the library of ActionCreators.