Of course it's more convenient, at least in big cities! One of the reasons I ride. Mass transit in NYC sucks big time. Running short errands by car is frustrating because of traffic and lack of parking plus high chances of getting into an accident and/or getting a parking ticket. If you live in rural area where "traffic" is something you see on TV, parking is not an issue and you have large distances to cover then a car would be more convenient.

I've run an errand last Saturday with my trailer: all the way to Manhattan, back to Brooklyn, stopped by LBS, then back to Queens stopped UPS (it was closed, duh...) and Post Office - all in just under 2 hours (about 25 miles) and it was fun and I got my exercise. Williamsburg bridge was packed with cars so were major approaches to it. Even with a trailer I was moving faster than traffic most of the time. Zero parking problems. It would take me around 2 hours just to drive to Manhattan and back, find parking on confusingly marked streets (or pay $25 for garage).

All while carrying quite a load that would be extremely tiresome if I were to carry it by hand on subway.

A.