I'm signed up for an AMGA single-pitch instructor course (to learn how to teach other people single-pitch climbing). One of the pieces of gear we're supposed to bring is a 30 meter static rope "for setting up big 'v' anchors." I don't own one, and the instructor says I can borrow one, so it's not a problem for me, but it makes me wonder why this would be considered such a fundamental piece of gear.
If I'm understanding the application correctly, the idea would be to extend the anchor so that a toprope doesn't have to go over the lip of a cliff, or allow the construction of anchors in which the pro is widely spaced. I would normally have used 1-inch webbing for this purpose.
Why would one prefer a static rope rather than webbing for this purpose? It's more expensive, and a 30 m length would not be useful for other applications such as canyoneering. What are the pros and cons?