It is not just a new style of credit card. And while it will act like a bank, it appears it will dodge regulation and consumer protection (limited as it is) under the word "cryptocurrency" or some other neologism poorly understood by the public and legislators.
Will Libra deposits be covered under FDIC? Will it be subject to closures when there is a panic? What rights do depositors have in the event of wrongful transactions?
So it's great if it allows people under repressive or kleptocratic governments more security and freedom. It's fine if it's just a toy to send money to friends. But it's another thing if it's just a bank with an unstated "depositor beware" philosophy. It'd also be a lot less worrisome if the company implementing it had a bit better reputation.