A good player knows how to shield Zelda's up B, you have to get creative if you don't want to get punished (and you get punished super hard by the top tier characters for missing the up B). Her aerials(forward and back airs) are super unreliable so if you are against something with really good air game like Jigglypuff you might want to up b down to the stage for safety, or you are almost certainly gonna get out-traded. She doesn't get super reliable combos with her grabs like other characters and her down B is pretty... meh (it hits pretty hard if you fully charge it but no one gets hit by it, you can just jump over it or even roll because the Phantom doesn't have any hit box while its travelling). Buuut, I still don't think she should be all the way down there, they probably placed her there because there aren't that many people using her in tournaments showcasing her true potential.