Bitcoin could be the king of crypto while Libra will likely to be the king of stable coins market, if I can decide which crypto to consider, I think this stable coin is not a crypto since they follow the norms of the centralized system.
Bitcoin and volatility are the key factors on why this market grows, if its stable, there's no difference with fiat and other digital currency, and people will not invest on bitcoin. its features is unique and very attractive for investors that's why it reached its current value now.