Salt tablets are just salt (NaCl) and salt on the table isn't.
I cannot see any reason for taking salt tablets except for a very rare condition called Addison's Disease.
Dehydration, sweating etc, one needs water, not salt which if taken will make your condition worse.
However in extreme dehdration, you might ,just might start to lose salt and require it either by mouth or intravenous infusion.
Of course in extreme cases of dehdration e,g ulcerative colitis, dysentery and other conditions of the GI tract you will lose salt and need replacement by intravenous infusion.
PP is correct, the healthy person doesn't need added salt.
Added salt is BAD for you.