I think it's a mistake to compare Libra with other cryptocurrencies - the only similarity between them is blockchain tech and its general function. Whole agenda of Zuckerberg's coin is completely different from idea behind cryptocurrency concept.
Even in his FB statement about Libra, Zuck have said that main purpose of this coin is "to create a simple global financial infrastructure that empowers billions of people around the world ". So it's obviously aimed in banking system, but it won't work like BTC and other cryptocurrencies. Libra will be more available, cause it will have whole infrastructure of FB and its partners (like Visa or MasterCard, so it's highly possible that you will be able to buy this coin in a seconds, in case of bitcoin such option is available only in services like
buycoinnow.com).
And one final thing - FB didn't use word "cryptocurrency" even once in context of Libra. But I believe both of them my coexist in peace
Yes, Libra is not a cryptocurrency. That's for sure. But although that fact, I think it can influence on cryptocurrencies. But there is one important thing - Libra won't be any danger for the most powerful cryptocurrencies like Bitcoin, Ethereum, Litecoin etc. This is only my speculation, lets see how it goes.