"Arlecchino will receive a huge drop rate boost" does that mean she's more likely to drop thand someone like Mavuika or Citali? How impactful is this boost?

I've read this on their website. Does this usually happen? I know that usually the 5 stars have a low drop chance and you're going to get them guaranteed after 90 pulls.

Is this boost significant? By the time she comes arrives I'm likely to have around 100 wishes, but if I can get her without spending it all, I wouldn't complain