WeWork does a lot of pretending about this, but it mostly takes the form of a social network web application. In the space itself, there definitely is not a norm of networking with the other randos at desks. The place has more of a library vibe than a makerspace vibe.
(I can only speak for the West Loop office, though).
I've been to both WeWork spaces in Austin (where I live) and the one downtown hosts a lot of events that I believe WeWork customers have priority at them (discount tickets and other things).
For me personally, I don't think it's hard to quantify at all. I'm absolutely terrible at being productive on my own, just having somebody to talk to that's working near me increases my productivity twofold.
Still, the price is really high. I certainly wouldn't be able to afford it if I was trying to bootstrap a new business.
To me it sounds a bit like playing the networking lottery at a very high cost.