There's ALSO always this point to consider:
The reason people want to see physical bitcoin is to enable BTC payments without being online. This does not do that. If, for some reason, I bought BTC on a CD or USB stick, the first thing I'd do is load the wallet.dat in there onto a computer somewhere and transfer the coins to another address. As long as I haven't done this, the original seller is able to spend the coins at will.
Well it all depends on the emitter's intent. If you traded a private key from an individual, you should redeem asap. If you got such a thing as a bitbill, you should consider the emitter has a very low incentive in destroying a sustainable business model forever to get a 1 day lotto like hit.
Yea, bitbills are good. The "put a wallet on a USB stick" is not.