Libra is what people want, not Bitcoin.
Who exactly wants Libra?
Crypto enthusiasts know better than to trust a centralized coin coming from a company with very questionable privacy practices.
Really? They know better? Oooh so that's why people are invested in all these centralized shitcoins. No they don't know better, they are just greedy and hope to make a quick buck and care little for the tech.
Libra starts centralized but will be fully decentralized after 5 years.
The mainstream could continue paying with Paypal and credit cards since it's all the same anyway. This way, they won't even need to pre-convert any money to Libra.
Why would i use existing services that charge hefty fees when i can use Libra with extremely small or no fees?
Lastly, since it's a stablecoin, it's closed off to speculators. You could argue that it might be able to replace Tether or some other stablecoins, but a lot of people use those to dodge regulatory mess that comes with trading fiat, which also comes with trading Libra.
People don't need a speculative vehicle, they need access to a money system to participate in the economy.
Just because Facebook is used by billions of people doesn't mean they'll use whatever product Facebook comes up with, and the same is true with Libra.
Maybe, even if a fraction of the people will use it, it will still be a bigger user base than all of current crypto together.