It is a stable coin with a consortium of big companies as the validator. If Libra reserves genuinely backed by a 1:1 ratio, then I don't see any serious problem. However, If they use the fractional reserve, I'm afraid inflation will speed up rapidly and take down the global economy (assumed Libra would become mainstream). Perhaps this situation is good for Bitcoin. People will realize that Bitcoin is the only non-debased currency.
Do you think US government will just watch Libra coin taking down USD while inflation killing it?
Though really, there's some investors that switching their investment and getting ready to invest on it and leaving some alts dumped.
If their crypto is going to be reserved by dollars, euros etc. then this is the definition of Libra notion.
I hope they can prove it that they're really backed by it or it will be just another issue tho.