I agree re: testing, and that's my primary use for noise as well.? If you operate CW though, it's nice to be able to hear to copy in a set of headphones.? FLDIGI and others don't usually print CW very well, particularly if the op has a "swing" or a "ham fist".?
I suppose, other ways to accomplish this in Windoze include the Virtual Cable drivers such as VB Cable and others?
Mitch Winkle