I would like to make a prediction that Facebook will dominate the Stable coins.
My biggest problem with using Stable coins is a lack of trust. I worry that Tether or any other stable coin will issue more coins than they have in reserve and therefore risk collapse.
With a Facebook coin, it seems like there would be little need to worry. Their market cap is like 500 billion. It will become the number one choice for people wanting liquidity to buy or sell bitcoin on the price swings.
Whether or not a Facebook coin would be attractive for remittances, I don't know.
As for Facebook coin threatening other cryptos, Ripple, or Stellar, I don't think it will. The main benefit of a crypto currency is profiting by expanding the money supply. A stable coin cannot do that.
If you have the ability to vote, please consider voting for my Deylandra project.
It involves cooking from home and selling food to your neighbors using crypto currency. It has billion dollar potential and can revolutionize the food industry by reducing the cost of restaurant food by 50%.