Basically speaking, on cpu hungry app, the processing of the sound will be offload from the cpu if using something like the sound blaster live (due to built-in sound processor on card). In respect to mame, I have not really found anything that will even sweat the cpu a bit unless you are running some of the modern games.
I would say it would slightly increase the performance if you are running something that are cpu hungry, otherwise nope. In your case, if it's just seating around, just put it in there.
Sound quality wise, there's no difference in mame.