SF supermarkets are for all things Asian food.
If you're looking for a vegetable, sauces, rices, ramen or snacks that they don't have anywhere else then SF is a place to check out. I've been to SF a handful of times for some Asian veggies, sauces, rice and just to walk down the isle of ramen.
Don't expect it to be like other grocery stores but if you're in the city looking for something very specific, it might be the place to go for you. I go or have been to almost every supermarket in Vegas depending on what I want or need to pick up.