Obviously this is aimed to stop Facebooks Libra. It is certainly seen as a threat by the central banks and the Fed in particular.
A ban will be difficult to install, if it only affects some cryptos, and not some other. The only option I see is, to ban all cryptos - but that will be also difficult, since many don't have a entity or company behind them that can be made responsible.
"difficult" is the operative, word. To try & stop a decentralised system might be better described as "impossible". It is the line between "big tech" and say an amazon, or some other large corp that will be so grey. But it is fun watching the USA regulators try & stop true global cryptos (libra is not really in same category).
I guess "difficult" is the better expression. Dont underestimate the power of the rulers. Its not a question of "can they do it", rather a thing of "how many laws, personal rights, constitution clauses ect. are they prepared to ignore".
This is a battle for world currency domination, so you can assume that those who are in power now will do just about anything to keep the status quo.
It will be interesting to watch where all this is going.
I think if Libra can be established as a stabile international currency, this will be the Kryptonite for the central banks and the state issued currencies in the world. Of course the same can be said if corporations like Alphabet or Amazon issue similar currencies.