In my experience, those who play from a set of tees that they shouldn't based on their distances, it comes down to ego. I often play with a friend who is 68 years old, doesn't hit the ball very far, but refuses to play from the red tees because he deems it "Ladies Tees". We use the term "Seniors", but that doesn't change his opinion.
A good rule of thumb as to which tees to play from would be to calculate how far you hit your 5 iron, and multiply that by 36 (shots in regulation par 72). So for example, 180 x 36 = 6,480 yds
As far as pace of play, I'm not sure, but it would lead to more enjoyment, hitting more greens. At my local muni, a 6,200 yard par 72 could average over 5 1/2 hours in peak season. Last weekend, on a rather cold (42 deg) but sunny Sunday at mid-morning, my foursome arrived at the first tee, which was backed up with groups waiting to get out. We played in 4 hours and 10 minutes on a crowded course. I'm sure most of the golfers were avid golfers, and thus play ready golf, but I'm sure the colder weather had something to do with pace of play. Play ready golf, spend less times reading putts from every angle, etc.