I've had them on a few occasions. On each instance, it was during lunch, and I was not hungry again the entire day. I think one packs enough calories for an entire day.
When it comes to defining roadfood as uniquely regional, I'd say the panzarotti is one such food. You really can't find it much further than Camden County NJ. Even try locating one in Philadelphia would be tough. On a 'micro' level, it's probably the equivalent of a steamed cheeseburger in Central Connecticut, but even more so. It's confined to Camden NJ and a few towns east, such as Westmont, Merchantville and Haddonfield.