It is centralized and same with other altcoins that's being run by a certain company. It would help bitcoin somehow by tagging itself as a 'crypto' because bitcoin is a crypto as well. There will be no ICO but it has a wide range of partnership, yes real partnership so it will have its own usecase. I think this is just another the same stablecoin.
Based on initial articles about facebook coins, facebook will create a stablecoin. But, it's not yet confirmed where it'll be backed from. Stablecoins as they say, is better than altcoins. Let's wait few more days for the official details of Libra.
AFAIK the launching will occur next year so most of the news that we are about to see these days are just about on the speculation of well known people and what they think about Libra. I don't usually use stable coins so it's really not a big thing for me but what makes me looking at this case is that it's facebook.