I think the short answer is one like, "if one had to because there was no other option." Like all hypotheticals it depends on certain presumptions that we could probably "what-if" forever. My first reaction was similar to yours, but after a little while I made the connection that spies are information gatherers, much like the nerves in the body.
I see that connection but question it's validity. The use of spies and cutting communication and finding various points etc. to me is the way of maybe a strategist pr maybe even tsun tsu himself but hardly a demonstration in analogy of his second post.
Sounds to me more like covert operations.