I think it really depends on the subject you’re learning. If you’re learning some sort of theoretical domain, such as analysis, you certainly have to work through every theorem - otherwise you won’t really understand the course of the subject. On the other hand if you’re learning applied calculus or linear algebra working through every theorem probably isn’t as great - by the nature of the class you’re already skipping over tons of theoretical details. I don’t like the black and white tone of this article.
This is incredible! Is the code open source?
Not yet, but it will be soon!
It doesn’t look like it but there is a draft of the paper available: https://arxiv.org/pdf/1707.07397.pdf
They have a «code» link that says «coming soon» — so, not yet, but hopefully it will be in the future.