These are very cool, perfect for Christmas gifts and great for introducing people to Bitcoin. You could install Mycelium on their phone and import the private key for them so they can use their funds immediately without issue, and by presenting them with the 'certificate' they have a tangible asset they can hold in their hands. I find that actually holding something that represents their funds seems to help non-bitcoiners get a grasp on the fact that this is actual currency.
Perhaps think of keeping a copy of the public address and top up their wallet a couple of days later so they get a sense of just how amazing Bitcoin and the technology behind it actually is!

And check they still have their wallet before topping it up again for their birthday, of course!
