In the US, cryptocurrencies are treated as assets, they are taxed every time you exchange them for something or even each other. I would disagree that libra coin is akin to Facebook and partners creating their own money.
Clearly you didnt read the whitepaper. Facebook (and partners) literally mint libra. You give them a dollar, they mint a dollars worth of libra and stick the dollar in their "reserve". What stops them minting more libra than they actually hold fiat reserves for?
This actually might be a blessing in disguise for crypto currency as Facebook will lobby hard to get that rule changed fast as people aren't going to want to report a line in their taxes for each of the hundreds of items they buy in their taxes.