I honestly doubt these are eco-friendly, the emissions from the factory making these will not make buying and recycling every single deck ever made worth it, in my opinion. Just like hybrid cars, you have to use them for some 40-50 years to make the car actually eco-friendly.
Well, I think the "eco-friendly" aspect of most products comes from its use, its being built of recycled materials, and/or its recyclable disposal compared to other, similar objects. Using your car example, the "eco-friendly" aspect of hybrids is that there is less fuel being burned in the usage of the vehicle overall when compared to a similar vehicle. Or, with these cards, they are being made with recycled materials (thus, not cutting down new trees for their entire construction) and their ability to be recycled (including recycle-friendly inks and adhesive, even).
Maybe a better word would be "eco-friendlier" instead of eco-friendly.
And, much like everyone else, I agree that the box is full of awesome. I really do enjoy the cards, as well; from the looks to the feel, they are great cards all around.