[stvnbn]

Why would I what to know how noisy is my neighborhood? That's something I already know.

[gpm]

1. You're considering moving somewhere.

2. Too get a relative sense of how noisy it is compared to others you don't have experience with, instead of just an absolute noise value.

[gkya]

This. You don't know how much noise pollution you're suffering until you experience some real silence. It causes headaches and such and it's nice to know that you can get away it.