Facebookcoin will be a very different beast and we don't know whether they'll allow it to touch any exchanges beyond their approved ones, and even the approved ones may only allow exchanging to proper fiat currencies.
If libra were to happen that would have been the best alternative to it but unfortunately it looks like it is going to be postponed for a while and probably even cancelled so I doubt we will have Libra as an alternative.Everyone was against Libra and the whole world wanted to stop Facebook from creating it and they might have managed to achieve that from the looks of it but what they are forgetting is that facebook would have been an improvement over the horrible companies we have right now, plus would be funny to see Winklevoss twins having a stable currency and Mark Zuckerberg also creates a better version of their stable currency
.Right now, the only one that looks semi-legit is USDC and even that doesn't look too comfortable to me right now so fiat is where I directly go to.