[PeterisP]

Well, in practice, public/private key encryption with large keys does achieve the same security, as does meeting in person (as required here) and simply exchanging a 100gb flash with a random OTP.

What this method does is makes it harder to attack if the Bob's key/OTP is physically stolen. ALthough keys embedded on secure chip-cards cheaply and commonly available now are just as secure - the authors apparently claim that the keys can be read off the glass blocks in less than 24 hours; and extracting a long key off a chip-card (even if it's just pin-protected with permanent blocking for x mistakes) would be a bigger pain, you have to physicially scan the chip with extremely expensive gear for that.

What this method doesn't do, is "make electronic copying impossible" or facilitate DRM, since Bob or anyone who compromises Bob's computers can freely copy and distribute the data right after the decryption.