Yes, well, I can imagine that under the assumption that people loose "faith" in Bitcoin, it's still possible to assign a "value" to the Bitcoin network, e.g. the hardware that makes it (miners and nodes) -- I wouldn't count the electricity usage as part of its value, though. But the point is that holding units of Bitcoin, i.e. knowing the secrets that allow spending them, does not give any rights on those hardware assets, so the value of the network cannot provide a lower bound to the value of Bitcoin units, in the same way that industrial or jewelry usages of gold does give it a lower valuation bound.