I never mentioned aquarium salt; I would use ordinary table salt in the event that I found a nitrite spike which could not be controlled by water changes, and believe me this has happened.
In an ideal world it wouldn't be necessary, but in real life newbies often overstock a new tank to the point where water changes will not control nitrites, and many LFSs will not take fish back. The newbie has no option but to brazen it out. In these situations, salt is a cheap and effective prevention of fish loss through nitrite poisoning.
We need to agree to disagree I think. "Ordinary table salt" shouldn't be used for anything because of the additives. I was one of those newbies (hence the name) with a drastically over-stocked, uncycled tank. Water changes will keep Nitrites down. I was doing 75% daily until the tank fully cycled. Dosing with Prime in between WCs would be better than adding salt IMO.