On a technical level, yes. It's a meat packed into a cooked yeast, flour and water mix, to which condiments and the such can be applied. However, a sandwich consists of two non-connected pieces of bread, where as a hot dog bun is connected. So technically, yes, but philosophically the same but an entirely different entity. Same as how a phone nowadays has 2GB of RAM, a 2.0 Ghz dual core processor, graphics display chip, display and input devices, but it's a phone, not a computer.

Wow, this actually got me thinking, in theory it's a sandwich, because the buns are bread and there is meat, ketchup, mustard etc. in the middle. But from the other perspective, it's kinda of its own thing, as the bun is connected and leaves an opening for the meat, also the fact that the hot dog is generally held differently than your typical sandwich. So in conclusion, it's a totally different thing

That's like saying a taco is a sandwich. No.