We can't, of course, argue that, since Facebook paid 1 billion USD for Instagram, Instagram is worth 1 billion. Simple circular argument. So, why did FB pay 1 billion dollars for Instagram?
Now, the article compares the New York Times, a well established, global corporation, which reaches millions, has lots and lots of world-class talent, physical assets, and a defined business model with profits, as an alternative buy to Instagram. Which consists of 37 million users, most of them in Facebook already, and no clear business model. For roughly the same price.
And it asks us to consider what choice we would make, supposing we were on FB's board of directors. That's it. No deep questions on the fetishism of commodities or the marginal social value of this transaction.