Kosher salt doesn’t have iodine or other additives put in so you get just the pure salt flavor, in theory. In practice, there’s nothing to stop regular table salt being labelled as kosher salt, in the USA at least. There is Kosher certified salt too, which is labeled as such.
Fancy salts like you listed remind me that salt and salary share a Latin root. Whereas Roman soldiers may have been paid with salt, now you need your whole salary to buy fancy salt.
