There are many similarities and only a few differences between table salt and kosher salt. Kosher salt is not a salt used by Jewish people that must keep kosher. Kosher salt is used to cure the meat, this is what makes the meat kosher.
Table salt is made up of many fine particles and shakes well from an ordinary salt shaker. Kosher salt has larger grains that chefs prefer cooking with. The larger grains makes it easier to measure "a pinch of salt".
Both table salt and kosher salt taste alike. Table salt tastes metallic because of the iodine added to it. Potassium iodine, sodium iodine and sodium iodate may also be added to table salt. An anti-caking agent is usually added to table salt and may be added to some kosher salts.
Because kosher salt does not contain any additives it tastes lighter and less salty than table salt.
There is no difference in nutritional value between the two types of salts. Our body needs salt to function, and salt in any variety works well for that purpose. Salt is used in many dishes. Imagine the flavor of food without salt. How bland would it taste? Most cooks use table salt for every day cooking, and all cooks and chefs use table salt for baking - since kosher salt does not absorb properly.
Some chefs prefer kosher salt for the milder flavor. Kosher salt is ideal for curing meats because of the larger crystal size that absorbs more moisture than table salt. Some people even love to use kosher salt on the rim of margarita glasses. A lot of Sea Salt is kosher grade salt.
It is all right to use kosher salt in cooking. However, remember that kosher salt has larger grains that absorb more liquid than the small grained table salt. Always add more liquid to accommodate the kosher salt.