format is only the border and the title block with the information in it. If you want you may also want to add location grid information into the format which gives the location of the view including the sheet and the grid number
on the other hand template may or may not include a format but additionally you can add views into your template, the BOM, some notes, things like that and also you may have a specific dtl file for the template which helps you to control the settings centrally. I can say templates automates the process up to a level than you can detail the rest