The phrase "noisy places" refers to locations or areas where there is a lot of sound or noise, making it difficult to hear or have a quiet environment. Full definition
I'd also add that, despite the noise cancellation, these little buds don't get super loud, which is something you'll notice in noisy places like the subway. (gizmodo.com)
On speaker mode, the speaker was fairly loud and should work in mildly noisy places like busy offices and in the street. (ubergizmo.com)