There are hundreds of USD stablecoin projects in the global cryptocurrency market.
Some are backed by real dollars and others are backed by big ones.
However, they are good and even more are needed, because they help make $1 more valuable by sending it into niche projects little known to the Federal Reserve Bank of the USA. Also, by this same dollar circularity, they make the printing of more dollars destructive to all stablecoin investors.
USD stablecoins are also not like the housing CDOs of the 2008 financial crisis. That was a scam in which a house was lent to the same person, 2, 3, etc times.
Here, a dollar is lent to multiple people at a time. A good thing.