A certain amount of the snicker may come from thoughts I have about cars when I hear "bondo". Growing up, anyone who was serious about car restoration found unrusted body pieces or cut out and replaced the metal... and then there was always the kid who had a car that was one big ball of unpainted or just primed bondo.
Just a thought. I've used the same types of fillers in certain situations and have no issues with it. But when I hear "bondo" I think crappy, unpainted car... even on a home repair page. =)