Not sure if you have experienced martial arts. It's constant learning. Sparring is a small part of the process. See kata in karate, hundreds of moves and transitions in BJJ, etc

100% agree. Not to mention that the goal of a dance partner isn't usually to surprise you, whereas in most forms of sparring, you are constantly trying to anticipate your opponent and adapt to them.

Anticipating and adapting is how lead-follow dances work, especially when your partner is not your usual partner. The follower anticipates and adapts to the leader, the leader anticipates and adapts to the follower's skill and knowledge level. A good lead will make the follower look good and feel good. A leader is also responsible for collision avoidance with other couples, and enables the follower to have confidence in moving backwards.

Think of it this way. It requires enough of your brain that you cannot carry on a conversation at the same time. If you're out jogging, you can have a conversation.

I generally agree with you, but GP and above were talking about martial arts, not jogging. I expect there's likely not much conversation going on between sparring partners, either.

The post I responded to did not mention martial arts.

I'm confused. All of the posts you replied to in this chain mentioned martial arts -- maybe you didn't understand that sparring is part of the practice of martial arts?

I interpret sparring is something boxers do. I never thought of it as a martial art.

No, I'm not familiar with martial arts. I didn't consider it an exercise routine.

Wax on, wax off?

With most martial arts you are constantly learning new material comparable to dance (that's to say nothing of martial arts like Capoeira and Silat which incorporate dance into their training).

It is also quite common for martial artists to add new skills that cover different aspects of combat. E.g. once karate-ka have a solid foundation in unarmed combat they often learn to use weapons. Practitioners of striking oriented martial arts commonly cross train in grappling or throwing oriented arts. Practitioners of Northern Kung Fu (generally focused on long range) might train in Southern Kung Fu (generally focused on short range). Many martial artists also incorporate supplemental practices such as meditation, qigong, or hojo undo.

So those square dancers are constantly coming up with new material? Ballroom innovators are patenting never before seen ways to articulate the human body? Sure.

There are many, many styles of ballroom dancing. You're never going to run out of things to learn.