It's important to factor in the importance of reusability. When someone makes a D3 visualization, it is infinitely reusable and hackable. So next time you want to make a map of killings in Chicago, you have it ready to go, and you just plug in the data, rather than having someone re-make it by hand. When you're a news organization, where speed is obviously of the essence, this investment has to be a no-brainer.

As Bostock's incredible skill is deployed on a variety of visualization problems, the New York Times builds a library of visualizations and templates that they can use for the foreseeable future, as long as the data is in the same format. That is incredibly valuable.