I'm certainly not 'More Knowledgeable' but I've always assumed the higher the ISO the more the Digital Noise. Perhaps that
someone had a particular situation in mind like fast moving or fidgety subject and was assuming higher ISO would be of net
When I use my D7000 topside I resist pushing the ISO beyond 800 will occasionally go up to 1600 but usually when bathed in
light trying to catch a bird in flight or some such.
THIS shot of a Robin was taken at 1600 backlit in the late afternoon with some flash fill. The higher ISO doubtless helped me
get the shot but the noise is there for all to see. Settings- 1/400,ƒ/6.3, 500 mm