In my wildest opinion

I think currency is used only as MoE and UoA. It doesn't yield profit, doesn't have intrinsic value, doesn't have to be pegged with anything (at its final form). The problem with the fiat however, the government keep playing with the supply (inflation).

The consumption-based economy failed to predict that humans are incredibly greedy, lazy, risk-averse, etc. Instead of using the increased money supply to do productive activities, they use it to inflate assets/commodities.

Treating currency like stocks, that can yielding profits, have a predictable outcome, the greediest people will compete to have the biggest pie. And do nothing.

Maybe currency has to be pegged with gold as in a true gold standard, to reduce speculative behavior.
And then slowly and silently partially detached from gold (after WW1 - Bretton Woods).
Then completely separated from gold (Nixon).

The funny thing is, a lot of people still think that currencies are "backed" by gold. I believe this is why the currency is relatively stable because the uninformed don't understand. The perception has penetrated the deepest subconscious brain area, that the money is stable.

A similar event occurred in 98 when SE Asian countries abandoned pegged system (USD) and then used the free-float system.

Cryptocurrencies, without first pegged with something stable, would end as speculative assets.