Though really that analogy isn't to say small groups shouldn't use non-fiat currencies. It's referring to an economy as a whole using them and not being able to

Though really that analogy isn't to say small groups shouldn't use non-fiat currencies. It's referring to an economy as a whole using them and not being able to use Keynesian techniques to smooth boom/bust cycles. No one could stop "ByteCoins" from coming out and issuing similar currency that might be backed similarly - unlike the problem of not having anymore gold. As this happened more, people would create synthetic currencies (like the IMF's SDR) to hold a basket of these goods - which would probably be adopted by many, or used for collateral for risk-mitigation instruments. TL;DR: Yes, there are some problems, but this doesn't have many of the issues the gold-standard did.