Yeah the dollar isn't backed by gold lol so you could use the death of the gold standard as a counter argument.

Blockchain technology has various applications and the blockchains they will run to encrypt patient records in hospitals (etc) won't be held to the same standards that blockchain cryptocurrencies are held to.

In the future centralized blockchain currencies could be launched, albeit as a new Banana Republic gift card or something, but those will have less appeal to investors and shouldn't steal from DEX market shares.