Sea salt is, as its name suggests, salt that has been evaporated from sea water. This truly natural salt contains a variety of minerals that are not found in table salt that give it an interesting flavor. Depending on how the sea salt is processed, it may have a different crystalline structure or color that make an interesting contrast to ordinary table salt, and when added to a juice shortly before service it provides a “mouth feel” that is different from ordinary salt.
Sea salt contains tiny amounts of strontium, which may help maintain bone health (although the sodium in both sea salt and ordinary table salt when consumed in excess is detrimental to bone health). It also contains tiny amounts of boron and silicates, which some report helps improve joint pain. It doesn't contain appreciable amounts of iodine, although kelp and other sea weeds do.
There is no major net health benefit from sea salt, but it is no more harmful to the body than regular table salt. Use sea salt or Himalayan salts in moderation to add interest and flavor to juices and other foods. The more identifiable the salt (the less it is dissolved), the greater the flavor.