As an electronics nerd I think of it like this.

The body is basically a semiconductor electronic device. You are 70% water, pure water being an insulator. Salt is the doping agent that makes the water conductive.

So not enough salt, the control signals can't pass through the transistor gates. Too much and it all leaks out instead of following the desired path.

Do a quick check and you'll find that not enough salt and too much salt have the same symptoms. Makes sense since they both lead to the electrical control signals in your body not following the desired paths properly.

Salt is so important it is the only micronutrient you evolved the ability to taste. Your desire for salty foods changes based on your need too.

TLDR, if you are gnawing on a salt lamp like a golden retriever with a bone, you probably need more salt in your diet.

There is an exception, some people genetically can't clear salt as well. Easily self tested with a home blood pressure cuff. I started supplementing salt and my BP dropped, I have a genetic double whammy of high salt need though.