To both questions, the answer is YES. However, it has to be regulated. You don’t want your cat eating too much salt. You can tell that cats like salt in this video from TikTok. He is very interested in licking a Graham cracker. My assessment is that he likes the taste of salt in the cracker (and perhaps the fat from the milk ingredient). The ingredients when making Graham crackers includes 1/4 teaspoonful of salt. The nutritional info for Graham crackers is 74 mg of salt or 3%. The chemical name for salt is sodium chloride and it is listed in the ingredients as ‘sodium’.

Sodium is a mineral. It is important for normal muscle and nerve function in both humans and cats and of course other animals. The level of sodium in a cat’s body can be affected by vomiting and diarrhoea. Also, Addison’s disease can affect the level. Sodium is vital in the transmission of nerve impulses throughout the nervous system. Nerves would not work without sodium and sodium works in conjunction with potassium, another mineral.
As a treat, my cat likes cooked king prawns. He likes them partly because they are salted. I don’t know by how much but there’s no question in my mind that there is some salt on them. This is confirmed by the fact that after he eats them, he drinks water because he is thirsty. Salt dehydrates. For this reason, I limit this treat. You don’t want to give your cat too much salt and the same applies for people. Salts increases blood pressure in people.
That said, I see no harm in the occasional salty treat for your cat as long as it’s strictly regulated. Cats can taste salt. They can’t taste sweetness and therefore unlike people they don’t take pleasure from eating sweet things. For humans sweetness can become addictive. Fats such as in milk are also tasty to domestic cats. Cats like cream and milk but the trouble is, in general, cats are lactose intolerant and therefore cow’s milk is not really great for them. Graham crackers contain fats through milk.