Dr. Art:
Fair enough question but personally I'd like to consider the question more as a hole by hole question to see what multiple tees do for any hole. On some it can be wonderful for variety and others maybe not so much so or not at all. And then, of course, the question of aesthetics does enter into it for me.
In most things to do with architecture I think it's always best to not become too formulaic about anything and get into simply yes and no answers to everything or every subject. Every hole in golf architecture should be ideally as unique as it can be, varietal, different etc etc.
Maybe this question is somewhat like the way I feel about fairway widths. I like variety in fairway widths of holes on a course--some wide, some maybe narrow, some whatever, all depending on what the hole is giving various golfers in the unique designs of any hole. The idea of standardized fairway width, particularly on some of the old classic courses is thoughtless, in my opinion, and apparently evolved into that for the wrong reasons. The same may be said on the question of any hole's tees.