Peter,
I think I know what you mean, and in reality, it could be described with several opposite or near opposite phrases - Championship vs. Recreational, for one.
I would guess purpose means shooting a personal best on any given course, maybe establishing a new one from the next set of tees back.
I would guess purposeless would mean being out to enjoy the camaraderie of being with your best golfing buds, which actually is a purpose, perhaps even a more lofty purpose than shooting your best score, depending on your view of life......
I have made this point before, but yes, every course has a design aimed more one way or another. I suspect TD aims more towards "purpose" and I generally aim more towards, if not purposelessness, then "camaraderie" in my designs. While those kinds of courses won't get me as famous as JN, TF, or TD, I believe I have numbers on my side (i.e., more golfers play without purpose)
I "purposely" aim for courses that you can play everyday, and not beat you up (and frankly, looking back at the hey day, probably missed the mark a little on some of my designs, striving too hard for purpose) Back in the old days, muni courses were designed with the purpose of getting players through the mill, factory style, which is a whole nother level down from designing for camaraderie.
The differences are in a lot of little details. I was reminded on the cart path thread of a client who hated the idea of those individual carts. While they might solve the problems of turf wear, and maybe slow play, they would reduce the camaraderie of sharing a cart, which he would never give up for his golfers, figuring that was really the highlight of their day, along with a few good shots to brag about......to the guy sharing the cart.