There are a variety of reasons why your cat may enjoy Spam. The first possibility is that they simply enjoy the taste. Cats have different taste preferences than humans, so what we consider to be unappetizing or even repulsive, they may find delicious. If your cat enjoys the taste of Spam, there's no need to worry – it's perfectly safe for them to eat as long as it's in moderation.
Another possibility is that your cat is attracted to the smell of Spam. Again, this is due to their keen sense of smell which is much more sensitive than ours. To us, Spam smells salty and greasy but to a cat, it might smell like a tasty treat!
If your cat seems particularly interested in Spam, it might be worth keeping an eye on their intake and making sure they're not overeating as too much fat can lead to weight gain and other health problems. However, if they only enjoy the occasional nibble then there's no need to worry – let them indulge their curious tastes!