Great question, so as such I had to put some serious thought into it.

many people out there seem to see Libra as a threat to current monetary system. I'm one of those. However I've learned that global economy is build on debt. And all debts are in FIAT currency. So does it really matter if people use Libra to pay for their "groceries" and shop online? They still need to pay all their debts and mortgages for next 20-30 years in their local fiat currency.

Facebook is draconian, their public surveillance and intrusion methods are unmatched. I could sometimes search for a term on Google, go to another device on an unrelated Facebook page and it would show me ads or posts based off my previous Google searches and I just know it couldn't have been a coincidence. Happened recently with audio equipment I looked up on Google and I mentioned something about it, and Facebook was showing ads for it the second I logged in -- from an entirely different computer.

It's an issue of control if you ask me, and instead of using something like Libra I'd use a more sovereign currency like BTC or Litecoin. Libra's getting a customized blockchain and they now have the financial backing to design something with a ridiculously beautiful whitepaper. The thing is, it's very centralized which goes against everything I stand for with decentralization. It will only be open source on paper.

I believe by using Libra people will just strengthen the institutional stranglehold. They'll either start wising up fast or risk facing the imperial choke out before needing resuscitation.