(One of the odd M.C. Escher works that doesn't explore impossibility)
I love to daydream. I daydream because it's a great stress reliever. And for another reason. I'm currently withdrawing from nicotine(snus) which is, unfortunately, the elephant in the room. Luckily I can still drink, so I'm not actually seeing elephants. I just know at least one exists, in some other dimension or in empty space.
Tobacco is a drug that breaks all rules. At first a deliriant/great-way-to-get-your-buzz-on, quickly tobacco use by the tobacco user becomes 'a way to concentrate'. Later on, the withdrawal consists almost entirely of 'feeling incredibly spaced out.' How perfect is that for the continuation of use?
Granted, nicotine is being researched for its ability to help ADD and ADHD people concentrate. Consider that Adderal is suburban-Meth and Ritalin is suburban-Coke. It's only a matter of time before nicotine is a pill and your children will be buying it(or a derivative of it) on their college campus to help them study after too much booze and pot. And that begs the question- how important is concentration?
Concentration is important if you're operating a motor vehicle, a meat slicer, a gun, or a knife. Simple matters of creating-or-avoiding bloodshed benefit from concentration. As for creation of art, I suspect that most artists who value stimulants(past and present) believe in magic. By that I mean that they value precision, concentration and clarity only because they think that there is a single great addition to their field that is housed inside of their brain somewhere. In other words, they think that they're special.
Great truths and perspectives frequently appear out of nowhere. There is a known phenomenon in problem solving; solutions often arrive 'all the sudden' while the problem-solver is spending time away from the problem, 'not' thinking about it. One proposed theory is that the unconscious mind is working on the problem during that time.
I'm not sure if that's true. I suspect the truth is that concentration and attention can itself distract. Concentrating and being as 'in the zone' as possible can produce a mental tip-of-the-tongue syndrome. In addition, whatever a person is concentrating on may be a red herring. And this comes back to magical thinking. When creating art, remember that if you ever express any unique perspective or truth, it will be on accident.
"I had nothing to offer anybody except my own confusion." - Jack Kerouac
(Though he might have been on amphetamines when he said that.)