Interesting question. I think of a sandwich as being two unconnected slices of any type of bread with some filler between the slices. A chili dog, on the other hand, is filler in the middle of a bun which has not been cut open. Same with a pita pocket.
Hmmmm ... so, here's how my mind works. I read SpunkySenior's answer - then wondered what if the bread completely wraps the chili dog? OH! Then it's a chili corn dog. Is that a sandwich? I don't think so. At what point is it no longer a sandwich, if the separation of the bread is not the deciding factor?
So, I will have to agree with SpunkySenior ... it is not a sandwich because the bread portion is (intended to be) connected.
Yes it is, and most people eat hot dogs with their hands. I don't. But I don't eat hotdogs. And I hardly eat anything with my hands. Hershey Kisses, yes, use fingers. Sandwiches , fruit, and pizza are all fork/knife foods for me.
Fingers were invented before forks. And create less washing up, as you have to wash your hands anyway. Using cutlery for finger foods is useless make-work.