Because restaurants don't want businesses like DoorFash to scrape it.

Is that at all effective? If you want the data to be publicly available, you have no choice but to make it publicly available. Whatever inconvenience a heavily JavaScript experience can add to motivated scrapers is just not significant.

I think it's just a keeping-up-with-the-jonses sort of thing: If the restaurant down the street has a flashy website then I guess we need one too. Having restaurants in competition over the quality if their website is a negative sum game because it distracts them from the food.