There’s a trick to using box graters that most people don’t know (I certainly didn’t until recently)
- Lay a towel or some parchment paper in a sheet pan (optional)
- Lay the grater on the pan
- With your non dominant hand, hold the handle of the grater and the rim of the sheet pan
- With your dominant hand, grate, pushing away from you + into the countertop
The mechanics of pushing down/away are much better than holding the thing upright, dangling it over a bowl or whatever. Easy to just push with your palm too (and keep your fingers out of the way).
Having played a few of these, yeah, you hear it a little better as the player. They don’t sound that much different out front.
If you think about it, on an acoustic guitar the top of the guitar is the “speaker”, driven by the vibration of the strings through the bridge. That thin plate drives vibration of the air it’s in contact with on both sides, front and back. The vibrations from the front are desirable, because you want the audience to hear the guitar, but the sound projecting back is only useful to the extent you can reflect and redirect it with the body cavity and sound hole(s).
So yeah, to the extent that sound coming out of the side of the body is useful, these make a difference. It’s up to you if that’s actually important to you though. IMO these are less useful for performance situations, more for people playing for themselves (practicing, etc.)