Stems are awesome! I understood some years ago the massive advantages of using stems in my set and it makes no difference what becomes commercially available to me as a DJ.
Producing them also myself… Stems and the amazing step sequencer (Traktor S8) give me the tools to be unique. I create spontaneous edits! This multi-channel audio file splits in 4 elements. Imagine the variety of arrangements proposed on Traktor S8 with 4 decks including Remix Deck with my own samples.
NATIVE INSTRUMENTS opened a whole new world with this technology. Mastering stems produced in studio does require a special attention. I can’t take the risk to clip my sounds when I perform on a stage.