It’s fairly straightforward to get this working (certainly no code is required, just SharePoint designer) and the technique could be used to automate all manner of business processes. For example, you could create an ASPX page containing drop down fields and calculated fields that automatically creates a quotation document or you could have a form that captures all the details for a job vacancy that would create a standard looking job advert.
Great for capturing client proposal data for later tracking purposes, and generating a shell template including relevant fields. With a little added controls and quick parts magic, I could foresee having SharePoint list choice column options dictate a cover page graphic. Lots of potential here.