I think he explained it a little better. I totally understand that you'll learn to identify which frequencies and sounds belong to which instrument and in turn

I think he explained it a little better. I totally understand that you'll learn to identify which frequencies and sounds belong to which instrument and in turn learn to identify when those are missing. I guess that also teaches your ears to identify differences in other situations more clearly. That's what mixing and mastering engineers practice their whole career and get really good at.