Interesting posts.
I think that Dude draws a good analogy re wearing leathers whilst motorcycling. I haven't ridden a motorbike in many years, but always wore a minimum of helmet, gloves, boots and jeans, regardless of the weather.
I don't think that it is ridiculous to wear a flight suit in a light aircraft. Admittedly I rarely do this myself, but there have been times when I have, especially in a single seat airplane or one with tandem seating. It strikes me as less necessary when flying a spam can, in which one has a passenger to hand you things, or at least an empty right seat to keep your stuff on (how many pencils have I lost!
).
I have a Nomex jacket that I inherited from the Queen, and I'm happy to wear it when the temperature is appropriate. But although I have matching black trousers, I never wear them (to say nothing of the shiny boots!).