First - I strongly agree with everything you said. It's a steep learning curve to climb for something that doesn't really relate to any prior computing experience a typical student could be expected to have today.

The teaching time will go down if they stick with this - they'll learn what the common errors are, what the common conceptual misunderstandings are, and how best to present the material to their students. The 1 on 1 tutoring they did this quarter (hopefully) will have given them a lot of insight into what the student experience is like.

It looks like they mostly learned a lot about teaching, and how their educational system in particular works. If they're hoping to keep working in the educational space these two things alone will make their time worthwhile.

Anyways, it's a really interesting article by people who are both passionate about and new to teaching - it's a fun read.