Indeed, Facebook's Libra/Diem was strongly prohibited by the gov, and it's a perfectly good question why Circle and Tether had better luck than Facebook.

I believe that the US gov hated Libra's peg to a basked of currencies and disliked Diem's peg to national currencies. US gov wants people around the world to use coins pegged to USD. This way the international demand for USD absorbs some of the money mass that comes out of the printer while providing some goods in services to US for free... I mean, in exchange for the newly printed dollars.

The gov might not be able to shut down Bitcoin but it's more than able to beat you up. Be careful what you wish for.