The scam aspect have nothing to do with the fact that it is not backed by some collateral. Trying to equate it to fiat money in that regard is not helpful

Instead Blockchain is a scam because, among other things, the prices are highly manipulated, with a series of pump and dumps.

By that argument, stocks, especially penny stocks, are a scam.

The only actual guarantee of fiat currencies is to be acceptable for taxes payment. That's all. No one - in theory and except some cases like "national interests" - can be forced to sell something for dollars or else.

>The only difference: a government could force someone to exchange something useful for some paper.

That's a rather big difference. That's the difference between money and monopoly money.

I think crypto enthusiasts skip the “except” part for government legal tender.

At a minimum, central bank notes are required to pay taxes. The type of currency doesn’t really matter - when gold was the medium, most trade was silver, and the volatile nature of silver made life hard for constituents like farmers.

Crypto works as a transfer mechanism, unfortunately money laundering, finance schemes, and organized crime are the biggest use case.