A hot dog is most definitely a sandwich. It's primary delivery mechanism is bread, which is its main qualifier. You might be saying to yourself "But Daz.. a hot dog is only one single piece of hinged bread, not two separate slices". While you would be accurate in thinking this, I will point you to exhibit A.. The Lobster Roll.. it uses the same delivery mechanism of a single piece of hinged bread, yet is clearly accepted as a sandwich.
It is not a Sandwich, it is a Taco. If the bread is connected, it is not two slices thus not a sandwich BUT as soon as your 0.99c poor quality Hot Dog wrap rips, you just transitioned into a hot dog sandwich. Just like a Choco Taco is a Taco, even though it's filled with ice cream.
I will accept calling it a "sub"