I suspect it's a combination of the two. After all, I can't create the fire without magic but I still have to use my willpower and talents to keep it going. [ The more they talk, the more Strange is relaxing. It's so calming just to talk shop with people, to dive into theories and hypotheses that most would roll their eyes at. ]

As for efficiency, I haven't a clue. I'm from most people's pasts so my experiences with unmagical energy conversion are different than others. [ says the person who's STILL getting used to various levels of 21st century bullshit. ] But I've found that with smaller tasks like lighting a candle or filling a water bottle, it's best to do it yourself. My magic is more suited to larger works.