It’s a regional thing. Mostly in that part is a hoagie, but it differs in composition slightly and some areas it’s traditionally served hot. While purists scream inside like when you put pineapple on a pizza, the bread is grilled open face, the meat and cheese stack is warmed, it’s assembled and lettuce tomato and dressing and seasonings (maybe) are applied. It’s actually really good. Cold cuts fail because the cold fat coats your tongue like a condom and mutes the delightful flavors of the meats and spices. Warm or hot the fat melts in your mouth and the flavors are more intense. You could road trip Ohio to the Jersey shore and have one every hour of driving and it would be different