I am not sure either if this will greatly affect bitcoin, btc already survived so many trials before and I'm confident it wouldn't fall down from an "overrated" coin lol. Hmm, honestly I think the worst thing could happen is only that btc might lose a few investors or Libra fanatics might say things like "BTC is old, Libra is the new trend", "Libra is the new king blah blah" or other black propagandas. But other than that,  nothing too serious things will happen.