If you consider the current userbase Facebook has, Libra would surely have a hefty amount of initial users and that is a significant factor to their success. However, I'm not sure if it would have positive impact in Bitcoin. Non-aware people to cryotocurrency would surely just use Libra like it's just another digital currency and don't care much about privacy. On the other hand, those who are into Bitcoin already might not consider to switch to their platform because of such issues.