I would like to play devil's advocate
From this article I read
Unlike the volatility seen around other cryptocurrencys in the past, we believe that Libras focus on creating a stable, low inflation currency backed by a reserve or real assets is a differentiator. Further, unlike other stablecoins, Libra will not be pegged to one currency but instead a basket of assets ranging from bank deposits to short-term government securities.
https://www.c[Suspicious link removed]m/2019/06/18/the-difference-between-bitcoin-and-facebooks-libra.html
Will Libra Coin bring Down Bitcoin's dominance in the market, your thought?
Highly unlikely. If anything, it might help Bitcoin, once people start developing interest in crypto. As soon as they realize that Libra is not what it could be, and that Bitcoin is they'll move to BTC. Even if they go to some altcoin, it will be better than not participating in the crypto space at all. Libra will help the crypto space in long-term, even though that is not Facebook's intention.