If you have lots of metric names that change (new servers etc) in a defined pattern it is irritating to constantly have to create new dashboards.
With scripted dashboards you can dynamically create your dashboards using javascript. In the folder grafana install folder app/dashboards/ there is a file named scripted.js. This file contains an example of a scripted dashboard. You can access it by using the url:
http://grafana_url/#/dashboard/script/scripted.js?rows=3&name=myName
If you open scripted.js you can see how it reads url paramters from ARGS variable and then adds rows and panels.