Boost comes with pre-order, right? So...maybe he used the 'free' boost and had no other toons he wanted to play so used it to skip MoP content and get maxed professions. So maybe he didn't "waste $66 dollars" at all?
Also, as many people before me have pointed out and many more will continue to point out after me, this is just a couple hours of work time. Would I rather spend several days getting 1-90 or spend 2 hours working after my day would normally end in order to hit 90? I've considered doing this on a couple level 85 toons, myself for that exact reason...That having been said, I don't think I play the game enough to justify it for multiple toons, but the "free" boost? I'm equally as likely to use it on my 85 warrior as I am on my 60 hunter as I am on a fresh level 1.