Actually, they're far from that - in fact, probably the complete opposite I might add. They have a soft and 'fluffy' feel, they're light and smooth; just generally great to handle and play around with. From what I can recall, the cloest thing that resembles the thickness are Aviators, they're as thin as that (perhaps even thinner) but are a great deck of cards to use. The colours are amazing too, they are superb.
I would highly recommend checking out a few, 'cause they're ballin!
Yeah go for the Old Studs, and give them a try. Also, the New Studs are great... well at least I think so. As said before both are very thing, and handle like.... clouds? Marshmallows? Well whatever they handle like, I love them.
I have the new ones and they're feel pretty good. They are more stiff than bikes, but not that stiff. They're super soft and smooth when you first open them.
I have the Star Wars poster playing ards made by Cartamundi. It's my favorite feeling deck. I don't use it much, because I don't want to screw them up. Very stiff, but fan great. One handed fanning with the whole deck has never been easier.
Old Studs are brighter-colored and have a brighter-colored card box than newer Studs. In addition, Old Studs are a tad thinner than the newer ones as well.