Adding a skin/cover to the dome would have increased the price significantly. The objective of this project isn't to make a shelter, it's to provide a framework for learning about and playing with geodesic shapes.
That being said, our next objective (after the kickstarter) is to design a low-cost cover for the domes, then release the plans as open-source. Until then, you'll have to roll your own!
Checkout this webpage for some ideas: http://www.weasel.com/dome_cover.html