Dr Lawrence H.White mentions Bitcoins at 21Minutes in.
So removing legal tender status from US treasury coins and Federal reserve notes more generally would simply broaden the freedom to denominate debt contracts in whatever people want, not just dollars, not just gold, but they might want silver, they might want to say the debt is only discharged by cheques or wire transfers of dollars,
or it could be silver coins, or it could be units of foreign currency, claims denominated in consumer index bundles, or wholesale commodity bundles, (ah) or it could be Bitcoins.
Discussion thread here:
https://bt.irlbtc.com/view/43919.0