Isn't he also making the point that's a very effective way to triangulate the leaders of an org? That's just going to reinforce the NSA's inclination to do so.
I think the argument is that NSA already knows exactly how valuable metadata is, while the average person significantly underestimates its importance without a concrete demonstration.
The same NSA that publicly states "We kill people over metadata"?
If that's the type of things they say publicly at conferences we can only imagine what a more sensitive comment would look like. How anyone can underestimate the importance of that is beyond me.