Waste of school tuition perhaps, but certainly not time wasted learning any of those skills.

Are you really learning the skill, or are you sampling it? One semester is maybe 40 hours of instruction. Even twice that in practice puts you at 120 hours. I hardly think that is enough time to become a good skier, etc.

40 hours of skiing is 10 4-hour sessions. For a young adult in decent physical shape and with good instruction, that's enough time to establish a base of technique and confidence.

That's pretty much all you get in most undergrad courses anyway. It's usually an intro to, or first taste of, a sophisticated subject that would take a long time to master. It's only after many such intros (i.e. many hundreds of hours of study) that the student will begin to develop a more sophisticated understading of their chosen field.

In that light, is a 1-credit skiing course any different from a 1-credit astronomy course?

I’m a decent casual skier and I’ve probably skied about that much in total.

People are different. I knew a couple newbie ballroom dancers who picked it up incredibly fast. But they were one in a few hundred. Ballroom dancing looks natural, but it isn't. Every move works against natural body movement. It takes a while.

For example, when walking, one sets the foot down heel first. With ballroom dancing, it's ball first.