Reply to traktor kontrol s4 audio interface?

I want to buy a audo interface but i wonder if the build in soundcard in traktor kontrol s4 will work just as good? i believe it would be fun to learn to dj too side by side with music producing in ableton..
i have read that traktor + ableton is a fun and creative setup together.
With a audio interface you use less cpu power? right? does it apply to traktor kontrol s4 too?