Krugman's speech here (after the Portuguese one) is the best plain English justification for keeping a few economists around -- far fewer than are seen on the ground today -- that I've seen.
Just as countries never know when having a few scholars of medieval limerick practice or Polynesian route mapping will prove important or even critical, there's a place for having a few economists around, so long as they are the ones who actually trade in reality based thinking rather than the usual morality/religion that, surprise!, finds that The Science of Economics has clearly shown that the Right Thing is whatever the rich want. (As Michael Parenti says, the Rich today want just one thing, as they have always wanted just one thing: everything.)
It's a cliche that we're "over lawyered" in the US, and that's mainly because lawyers have a nasty habit of considering every question subject to debate. This has always caused ruling elites to prefer their economic ministers to their lawyers, because while there are always plenty of lawyers who will bow and scrape to the rich, there are always plenty who will insist on pointing out when the rich are walking around naked, thinking that they're wearing their finest robes, and that their policy prescriptions are not to be trusted except as a guide to how to get the rich more of what they want.
Not so with economics, which is much more ecclesiastical. Oddly, although the law is supposedly governed strongly by precedent and economics is supposedly a science, in practice lawyers are far more willing to challenge doctrinal authority and economists are far more political, taking their cues on policy by watching which policies get the nod from those in power.
One of the great victories for deception has been the statement that economics is the "dismal science." Everyone focuses on dismal, and the science word slips in past the BS detector and pretty soon everyone is walking around thinking that economics is a science.
http://libraries.fe.unl.pt/index.php/e-resources/nsbe-wp?task=callelement&format=raw&item_id=63&element=f85c494b-2b32-4109-b8c1-083cca2b7db6&method=download&args%5B0%5D=4e805d919ad9d771a43369740847e048