The benefit of having them in book form is that you can curl up in bed or on the couch to read them, at your ease. Even if you had a laptop, it wouldn't be the same as with the book. However, the Hypercard stacks can be searched, which is something you cannot do quickly with a book.

I suppose it would have been nice to have them in PDF form. But Apple put them in HyperCard format long before PDF became popular.