Reply to DN-SC2000 or DN-MC6000 (all-in-one or not)

Noob question here. I have been practicing with Traktor for a couple months and getting ready for my first bar/club gig (small place). I am more a musician/music-maker (dare say producer) but really want to start DJing regularly. I have been using my APC20 but I really like the idea of the DN-SC2000, more so even than the all-in-ones like the MC6000 or others.

Recent NAMM was full of all-in-one controllers (NS6, DDJ-T1, DDJ-S1 to name a few). Seems all-in-one is the preferred way now. I can see they are more cost effective and better if one has to bring all their own gear. But if one is going to clubs which are already setup with nice mixers then it seems a compact controller + laptop + (club external mixer maybe use clubs interfaces) makes good sense.

Just wondering if going the audio-interface + DN-SC2000 is still a good option, maybe more flexible for the long term?
Why are the all-in-ones so popular?
To all-in-one or not to all-in-one that is the question?