> Could it be said that bitcoins _do_ have an intrinsic value equal to the marginal amount of electricity and equipment needed to produce one?
No, that's an intrinsic cost. It would only be an intrinsic value if that electricity and equipment could inherently be extracted back from the bitcoin. The intrinsic value of gold comes from what you can use gold for other than a medium of exchange. Bitcoin has neither the intrinsic value of commodity currencies nor the sovereign backing of fiat currencies.
No, that's an intrinsic cost. It would only be an intrinsic value if that electricity and equipment could inherently be extracted back from the bitcoin. The intrinsic value of gold comes from what you can use gold for other than a medium of exchange. Bitcoin has neither the intrinsic value of commodity currencies nor the sovereign backing of fiat currencies.