Often, we confuse results of a process with the selection for the process. For example, why are Harvard graduates so brilliant? Is it because Harvard gives great instruction? Need not be. It could be because Harvard selects only the best of the best!
similarly, why do swimmers have such excellent physiques? Is it because swimming is great for building such physiques? Need not be. It could be because people with good physiques go for swimming.
So, does it mean that the process is worthless? Not really. Knowing about the Swimmer’s Body Illusion guards us against falling prey to false advertisements and promotional campaigns.