In a broad sense, all salts are sea salt — even ground salt. After all, the vast deposits that are mined from the ground were deposited there by prehistoric seas as they evaporated and receded.
Sea salt doesn’t really taste different from regular salt — salt is salt is salt. What can make it appear to taste different, as far as our tongues are concerned, is how it dissolves on our tongues — especially sea salts which are chunky or flaky.
Sea salt is extracted from sea water by evaporation either through the sun or through man-induced steam. It is very often cleaned to remove other undesirable elements that would affect not only the taste, but it’s saleability. In general, sea salt when first extracted from the sea is only about 75% sodium chloride.
In America, however, salt can’t be sold for human consumption if it is less than 97.5% sodium chloride. So if the manufacturer wants to sell it for human consumption in the world’s biggest marketplace, it needs to be refined. Once refined, American law says that sea salt packaging can’t claim nutritional superiority, because it is very similar to table salt after the refining.
Though there are many brands of sea salt, sold at different prices, often all come from the same source or refiner.
Using a good sea salt such as Maldon in cooking is like using extra virgin olive oil in cooking — besides being wasteful money-wise, it really just shows a fundamental misunderstanding of the product — that cooking actually renders the product quite ordinary and destroys it.
That being said, where it will taste better in cooking is in countries like Canada where regular salt is over-iodized, giving a harsh, chemical taste to food, and in those instances, yes, sea salt is better — but don’t use the expensive ones, just use the regular ground ones.
Regular, un-iodized ground sea salt is also better to use in dough recipes using yeast than iodized table salt, because iodine impedes yeast.
The sodium profile of sea salt is identical to that of any other salt; it has no health benefits in that way.