Do you have evidence for these claims? You say in a comment below that you link to references, but your first link is to a study that compares how different salts taste. The second talks about dehydration, but it actually says that increased sodium can cause hyperosmolar water-loss dehydration. I don't see any links besides those two.
When rehydrating, it can be good to replace electrolytes like sodium if you're exercising or sweating a lot, and maybe that's what you were trying to say. But the blanket statement that adding salt to your water always provides better hydration seems untrue.
Sodium is a critical nutrient, but have you looked into the potential health risks of increasing one's intake of salt? What are your thoughts on those?