What's the difference between bitcoin and the USD?

(If bitcoin is just fake money, with nothing of real value behind it, what is USD?)

$30t economy, full faith in credit, and Federal Reserve is behind the dollar, interest-bearing securities in which you can place your dollar with a relative degree of safety, USD still a very highly-rated credit despite debt to GDP levels. ... Ron Isana.

"It's a real thing." Comprises 65% of global trade. 95% of global exchange transfers. It's a reserve currency (bitcoin isn't, and "doesn't exist in any form except in the minds of those who created it.")

"We've done this a million times in the past, whether it's tulip bulbs, railroad bonds, electronics companies or bad internet companies. The underlying internet was important but a lot of the players like CNGI disappear because they had no functional use case"

Blockchain technology is useful though. (It is the underlying tech, and crypto is the overlay.) Cheaper, frictionless transactions, more secure, transparent.