"Mexican" Hot Dogs Taste Different?

In the San Francisco Bay Area there seem to be more and more Bacon Wrapped Hot Dog vendors showing up with their small griddle carts at large events like outside large concerts and sporting events. My friend in Los Angeles says they common there as well.

These carts and vendors are likely not licensed which doesn't concern me, but while they all sell the exact same product, a Bacon Wrapped Hotdog on a bun with you choice of Grilled Onions and Peppers plus Ketchup/Mustard/Mayo, the thing I find interesting it the hot dog they use.

They all seem to use they same style/brand of dog... which is a little chubbier than most "American" style hotdogs that I would get at a regular restaurant, ball park, movie theatre, or Costco. And the the TASTE and TEXTURE is a little different than standard dogs... not bad, just different. But they ALL seem to use this same 'different' hot dog.

I was wondering if this is the "Style" and these specific type of sausage is purchased for this style of hot dog? And what is the name of that type of sausage? I know you wouldn't sell people a Coney Island style hot dog with a Brockwurst sausage, and maybe this is the same thing? Or maybe I'm just used to a 100% beef dog and these ones have more pork or fillers? Or maybe since the dog may be the most expensive part, they always go with a standard cheaper frank?

Any Thoughts?