The notebooks are a rough guideline of the ideas necessary to build a solution to the problem we are trying to solve. I’d say think of it as the solution manual to the homework.
That said, a lot of what will be in the end result of the notebook (and what students are writing in their notebooks) is investigation into the dataset, seeing how the model is performing, etc. Not what is directly required to train the dataset.
I think Jeremy is working to demonstrate ideas and fundamentals throughout the notebook not build a working model to solve the problem at hand.
When there are issues that should be a non-problem because the general idea is there.