This is a nice find.
A normal turnip only does one percent of damage when used this way, winky faces and dot eyes a bit more. It's unlikely that you would get superimposed onto your opponent randomly in neutral, so this is definitely not a good approach option.
This might have potential uses as an OOS option. Done perfectly, the hitbox comes out two frames faster than a nair, so if your opponent hits your shield and is right on top of you, coming out with a turnip is (sometimes) a bit safer than coming out with a nair.
I did some rough hitstun calculations using SB's calculator, and it turns out that at higher percents, you still have the frame advantage after your wavedash ends. At lower percents, there's a possibility your opponent will be able to react before you even finish your wavedash. At very high percents where your opponent has enough hitstun for Peach to jump and Z-drop again, this might even be some sort of turnip waveshine against opponents that don't know how to DI it. It'd definitely be surprising to perform such a thing, but such high percents are already WAAAAYYYY past kill percents that such a thing would be pretty much swag-tech.
