I don't know about sedans (saloons, we call them over here), but convertibles are very useful for carting heavy stuff around. I seldom used the back seat of my Triumph Stag for anything else (yes it was mostly classic computer stuff, so this is just on topic). Of course when the Stag died (in honourable combat with a Volvo, FWIW) I decided to get an estate car (station wagon) to replace it. I now have a pickup and a van... Philip.