I don't know a whole lot about table salt, but there are a few things that I keep seeing. If the topic is interesting to you, I suggest you do some more reading.
Refined salt contains only NaCl (and iodine in a form that may be toxic, and an anti-caking agent that could be bad, too). You do need NaCl in your diet, but you also need dozens of other minerals, some in trace quantities.
Unrefined sources of salt that our ancestors used (bone broths, sea salt, etc.) had a complex mix of minerals. The refined stuff triggers the "I want" reaction in your mouth, but without delivering the other minerals that evolution has taught us we should find there.