Unless your into making music & using midi devices etc, then it would be essential to get a PCI soundcard with a Game Port seeing as they would be better and are dedicated to that work than on-board sound.
On-board soundcards these days are just for basic needs of the computer user so I'm assuming that is why they are missing them.
I can understand using the Game Port for joypads/joysticks, but these days, many use the easier USB interface. Though this may prove problems with people with older pads.
Anyways this is what I think of the subject.