To my mind a good crossword puzzle is like a fine wine - it is something to be savored so you can enjoy its bouquet, appreciate its complexity and nuance, and experience the full range of its pleasures. So I don't understand why anyone would want to finish it as fast a possible, or "swill it down" to stick to my metaphor. A finely crafted puzzle, like a rare vintage wine, is something to be enjoyed slowly and fully.
I was thinking of this today as I tackled the New York Times (syndicated) Sunday crossword puzzle while sitting in the sunshine on my back deck. The puzzle itself was not too terribly difficult and I could probably have completed it in an hour or so ("speed-solvers" take a matter of minutes). but the sun was warm and I wanted to prolong the enjoyment so I took the time to appreciate the cleverness of the puzzle's theme and to marvel at the answers that taught me words that I did not know; case in point, "___ oneself (share private thoughts)" produced UNBOSOM, a beautiful word that means exactly what the clue suggests, and which I probably should have known before. Speed-solvers, I should note, would likely have filled this word in entirely from the crosses, which were fairly easy, and may not have even seen the clue for this lovely word. It's their loss, and that's what you get for guzzling when you should be sipping.
So one hour in the sun turned into three (I moved on to the Jumble and the Cryptoquote after completing the crossword, to prolong the experience) and by the time the high clouds moved in and it became too cool to sit outside any longer I had spent some enjoyable time in the sun (and had gotten a pretty good start on my tan base) - why would I want to rush through that experience?
My philosophy is, to each his (or her) own. If you feel the need for speed, then go for it. As for me, I've always enjoyed life in the slow lane. Is that why I live in Maine, or is that because I live in Maine, I wonder? I'll have to give that some more thought.