well loof, just try knitting from a big old skein and see what happens!
How ya gonna pull it and keep knitting? You're not, that's the answer. You would have to put your knitting down every other minute and unwind the yarn in big circles from the skein.
When it's in a ball you can just pull at it, esp if it's center wound (coming out of the center). Even if its not center wound, you can keep it in a basket or bag and it unravels easily. so, there's that.
NOw! I'm wondering ladyindica, how much you paid for your yarn winder? Birch sounds lovely. But they're a bit expensive aren't they? I'll do a google. I'm thinking of buying a couple of nostepindes, nostepinnes... they look pretty neat too. But I guess your thingy goes much faster correct?