I say yes. The big FB starts to enter the digital currency and that demonstrates the blockchain will have a future.
Facebook jumping on the crypto bandwagon gives other cryptocurrencies a chance to grow tremendously as other investors get to know about the blockchain and cryptos...and get an opportunity to invest in other coins to expand their portfolios.
Can the launch of cryptocurrency Facebook can be a factor for the growth of Bitcoin? It is not excluded, since investments mainly in large currencies are made using Bitcoin. And I think Facebook is no exception.
You are right, unless facebook chooses to only accept fiat as a way to buy Libra, Bitcoin remains a beneficiary in this new coin as demand will skyrocket as investors try to buy the Libra coin.