The pattern of agile processes allows you to design processes in which you can skip an Activity or a flow, and switch between Activities or flows as required without breaking your data.
To create a model instance over a record with your business data can be useful in the cases when you allow your users to create entities for documents: The user creates an shared record from a document, for example, an order, and on submit a new model instance takes care of further actions over the entity, such as processing the order.