In Flux architecture, the UI would only fire an independent action with type and associated data to a dispatcher which would then update the model the same way any background ajax method would update the model.
"Client Side MVC is completely different than Server Side MVC"
"We are setting up a two way communication between two objects..."
"In short we are wiring together the value of the firstName property of the Person object to the value property of the input."
bindings in Ember.js can be used with any object, not just between views and models.