I would never use Libra, and I'm not sure there are many who would. But good luck to Zuckerberg, I'm holding 190c 5/1s, so hope they make some smashing announcement come earnings!
A dollar replacement with zero additional benefits (like those mentioned above) seems like the exact "solution without a problem" that existing "blockchain" tech was pretending to not be. TL;DR - this won't work!