Isn't the point of this approach to be _difficult_ to switch back and forth? Next thing you know there will be a chrome extension that swaps your hosts file and you will be separated from procrastination by a single click.
I found it useful to force myself to manually comment/uncomment lines in my hosts file. It gives a critical few moments for a bit of humiliation to set in, as you realize how desperate you are for diversion. On the other end, it gives a moment to mentally pat yourself on the back for eliminating the distractions.