I thought than in flux, the worker thread could send "push button" message to the dispatcher and it will deal with it asynchronously. Likewise, the updates to the views are asynchronous (and can be potentially multi-threaded) to the actions that are coming into the dispatcher queue.

The thing is that the entity that pushes a button is a human, not a worker thread.

It is very common to have async http requests that "push button" to to say when they resolve.