Some of the critiques above are the result of a lack of clarity in the OP rather then disagreement. I will clarify those areas and respond to the remaining areas of possible disagreement.
Fiat's advantages include reversible transactions with the ability to go to the court system in the event of fraud or theft.
Multi-party signature in Bitcoin and contracts in Ethereum allow for escrow and reversible transactions. The court system is orthogonal to which currency is used.
Perhaps but any transaction that might needs court intervention will need to be done in a non-anonymous way. Also at least for the immediate future the courts are likely to take fiat claims more seriously. I would argue that this is a current advantage of fiat although technology and case law in the court system may undermine this advantage over time.
Physically it is a comparatively a cheap system to run without the high cost of a proof of work system.
Not true. We have to pay for all the bloated government, VISA fees, and debt that central banking sustains.
Proof-of-work is much less expensive.
Correct but that is only our present condition. In theory without all the bloated government, VISA fees, and debt (stripped of all the fat) the actual technical cost to run a lean centralized fiat currency is (theoretically) cheaper then a decentralized cryptocurrency. I will concede that this condition is nothing like the world we live in today. The point I am making here is that in theory fiat may become cost competitive again in the (probably distant) future once the waste is stripped from the system. I will clarify the OP in this area.
Regulation makes the market predictable and acts to stabilize value.
Incorrect. Regulation makes everything less predictable because fitness is stomped on.
I concede this point and will remove that comment from the OP
Its largest weakness, however, is that it can be debased at will by the central issuer leading to an erosion of value.
The
erosion-of-value is a very positive and necessary function. The negative of central banking is the ability to direct where the debasement goes. It is crucially important to stop conflating these two. Seems all goldbugs are stuck in this conflation.
I meant that centralized debasement at will was the greatest negative of fiat. I will try and clarify this in the OP
Likewise for the other comments about debasement. I agree that gradual debasement over time is a necessary function for a successful cryptocurrency.
Transaction times must also be slower than those of a fiat system.
I believe there can be a technical solution to make them fast enough (as in seconds).
No one to my knowledge had developed such a solution. Until they do the statement stands on its merits.
We agree that top-down organization will shrink in relative size into the future perhaps after peaking first in the next few years. We have not fully explored just how much top-down organization is optimum or how quickly it will shrink. I suspect consensus on those issues would be difficult to obtain
However, it is the broad trends rather then the minutia that are important.