Art has to be built on craft, so mastery of the craft is important.
Some people are afraid of knuckling down, honing the craft parts, the learning how to control the process to make it work properly for themselves. They seem to think it will restrict their photography when the exact opposite is true, with mastery of craft behind you it liberates your work.
But if you stop learning and re-invigorating and expanding your craft then you become stagnant. On the other hand it's important not to be obsessive of technique.
So sound craft allows you to shoot confident the results will be the best quality possible under those particular circumstances. This craft is all the more important when shooting 35mm where control of grain, sharpness and exposure is more critical, it's what makes photographers/photojournalists like Salgado so highly respected, it show in the quality of his work.