This puts the hotdog not in the sandwich category, but in the taco area.

I mean…

… they’re not wrong

That looks delicious. I want it.

It also suggests pizza is toast, and an apple pie is a calzone.

TACO SAUSAGE!

This suggests that cannelloni and burritos are sushi.

Open face sandwiches are toast you heard it here folks!

Behold, sushi.

Diogenes is rolling in his grave

I think Cube Starch Theory is on the right track but the naming is off.  Perhaps the name should be of the oldest food that exists in that configuration, that being the origin ‘species’. i.e.

1. Flatbread
2. Sandwich
3. Taco (there is probably “food folded into starch” older than this but it’s not coming to mind right now)
4. Wrap
5. Bowl
6. Dumpling