I wondered this too but IMO, I don't think that you could get the same benefits of steam in the shower as you could with steam from the steamer. I havent bought one, yet, but I have tried the shower steaming, the heat cap and I even tried to do the steaming at the gym. The heat cap suffices, because that's all I have, the shower steam was a waste to me because unless your bathroom is small I don't see it being very effective- and I don't take showers that long. And I could not for the life of me stand to do the gym steam room- I couldnt even stand in there for a minute!lol.
http://hubpages.com/hub/Hair-Steamer...p-and-Benefits
I'm going to treat myself with a steamer because I really don't see any negatives. The price will ultimately pay for itself in a few uses- especially since some salons charge ridiculous amounts of money for it~ from an extra $30-$70! SMH
Maybe it could enhance the curl pattern.
BUY IT! Save up for it. It'll be there when you're ready to buy it.