Yes, the same could be said about folks who buy the cheapest dog food that Walmart carries, vs a more premium brand such as Orijen/Acana. Both will get the job done if growth is the only concern, but over the long haul clearly some feeds are far superior (nutrient wise) than others. I don't want my dogs or fish consuming corn, soybeans, or feather meal. That's not to say that one can't grow out nice looking fish that consume those types of ingredients, simply that for reasons already stated I choose not to.
FYI - on the new NLS labels that same formula will be listed as: Whole Antarctic Krill, Whole Squid, Whole Fish, followed by Wheat, Ulva Seaweed, Chlorella Algae, Beta Carotene, Spirulina, Kelp, Garlic, Alfalfa, Scallops, Omega-3 Fish Oil, Wakame Seaweed, Spinosum Seaweed, Vitamins, Minerals, etc.
Yes, there is still some wheat used as a binding agent, but less than what was previously used prior to the addition a few years back of the various algae and seaweed. Those raw ingredients also now help hold the pellet in a dense form which helps keep nutrients locked inside. (vs immediately swelling up with water)
You won't find too many (or any?) farm feeds that use Antarctic Krill, Squid, and Fish, as the primary sources of protein (amino acids) and fatty acids. The reason for that is simple, the cost. Much less costly for a manufacturer to use soybean, feather meal, corn etc, and lower grades of marine protein to supply those nutrients. They are also moving to a more consumer friendly form of preservative, Naturox, vs ethoxyquin, which also adds to the basic cost of each formula.
Just like in other pet food, you tend to get what you pay for. The bonus is that due to the quality & density of nutrients in the more premium brands, one can typically feed less, which results in less solid waste vs the lower cost farm feeds. In a closed system such as an aquarium that's always an added bonus.