I did not say anyone could not probably do that, but why have headphones on to listen to a game, and have speakers you probably can not hear that well playing something else. All I seen is that if I look at certain games, there is a folder called "music" for the game, and others put their *.mp3 files in there to not listen to the music of the game but to something else. Not all game have that, and it was already mentioned at Tom's Hardware in the first post that if the program can have another outlet for channels, then all of that can come out of one sound card, except it was explained by having two sound cards, but again why?
( Because you have two ears????)
Please, some games have surround sound and even 7.1 sound, so why not three different sounds coming out plus a subwoofer also, might as well make use of it all, three channels of stereo, and a subwoofer.
????
[Sarcasm off]

 
But really my old 2007 Soundblaster card had all of that, and yes I admit I did not use it with Sonar.
(and I could have done just that).