state-domain-mn-architecture.js
is one approach to separating application state mangement from view state. Application state is maintainted centrally by "Domain Controllers" linked to an event bus that each manage a model or collection. Application state models are then passed into the view hierarchy. Views can use Marionette.State to express their own data needs and "sync" what they need from application state. A Marionette.State instance, in this approach, lives and dies with its View and also handles view events to establish uni-directional, closed-loop management of local view state.
For a more digestable view of Marionette.State's utility in terms of views, see the following JSBin, which addresses the utility of Marionette.State without an opinion about greater application state architecture. It is a working, slimmed-down example of a view spawning its own State instance that serves to consolidate what it needs from global application state models.