I feel that Mangaka has done a slight against the concept of Tacos...
Other than the 'self -serve'/choose your own ingredients i don't see anything specifically 'wrong' with how he chose to do it
but you'd prolly get mad at me then, when i didn't have meat/proper filling i just spread some strawberry cream cheese on a tortilla and heated that up
it might not be as common in japan (tho i heard there was one city with heavy brazilian influence and had some restaurants there, the main chara in solitary gourmet went there in a live action?), but i'm sure as long as the meat's good, i wouldn't complain, though it would be interesting to see how well they'd do if some latin american chefs moved to japan to set up a restaurant or so, or doing some kinda fusion foods