This is false. Market cap is a meaningless statistic when applied to cryptocurrencies. If I create a billion 'FOOCoins' and sell one to a friend for $1, FOOCoin now has a 1 billion market cap, but only a single dollar has changed hands. He sells it back to me for $2, now FOOCoin has a cap of $2 billion! With only $3 having changed hands.

This is clearly an exaggerated scenario, but it does show that the market price multiplied by the number of coins is not meaningful.

> Do you really think that a 300-500 billion dollar market is being propped up by less than pennies on the dollar?

I don't think it's a 300-500 billion dollar market.

In fact the article you linked to goes on to explain this very phenomenon! That in fact it's possible that only around $6 billion in inflow has gone into cryptocurrencies, ever. This puts tether at around 1/3 of the entire inflow. Is that still trivial?