Usually you don't have to pay $20 extra for a steelbook though. Most of the time it's basically considered an "alternate" packaging to entice buyers (i.e. a blu-ray has been out for awhile, and then later on they re-release it as a steelbook to rekindle sales interest). In the case of video games it seems to be more of a pre-order bonus type thing (Ni No Kuni, Assassin's Creed III, Prototype 2, etc).
$20 for a blueprint and a steelbook is a bit of rip-off IMO. But then I tend to see most of the CE's as a dubious value - at least if you breakdown the items you get for the premium you pay. I'm sure some of them are a legit "value" for collectors, but to me alot of that stuff is clutter. Don't get me wrong, I've been suckered by a few CE's that I just couldn't resist. But both this special edition and collector edition are not really appealing to me for the price. I might have been interested in the CE if it was $99.99, although the "value" would still be questionable. At $149 it's a joke IMO.
Maybe since the CE doesn't seem to be selling, it will end up cleared out for much less. But then i probably will end up buying the game long before that anyway so it won't really matter for me.