If you search online for the Fed's own explanation for these policies, they make some overconfident assertions about "ample reserves" and how their policy assumes there are now "ample" reserves, so they can just set the reserve requirements at zero. Seems to me some political doublespeak in order to provide the unprecedented level of Keynesian stimulus that was planned to be released.
"OK, can we see behind the curtain?"
"Absolutely not"
"Can I cash them in with you to get the dollars back out?"
"Hell no"
That's why it's relevant. Because this is not a bank or bank-like situation, and comparisons to fratctional reserve are spurious. They're sold specifically on not being fractional.
https://www.ft.com/content/529eb4e6-796a-4e81-8064-5967bbe3b...
I would have thought that would be a fantastic reason never to go anywhere near the entire ecosystem, personally. Especially as their website is still doing it (or at least using weasel-words to heavily imply it) -
“All Tether tokens are pegged at 1-to-1 with a matching fiat currency (e.g., 1 USD₮ = 1 USD) and are backed 100% by Tether’s reserves.”