Here is the Bloomberg account, here are Krugman’s own words. I say it’s a good move and if I were in an analogous position I would do something similar. Think of it as another form of disintermediation. Think of it also as being closer to useful airports and media centers.
More generally, the value of living in either New York City or Washington, D.C. — for those who seek influence — is going up. Krugman’s decision reflects that broader reality.