If the pace and level of a lecture is such that you can both listen and write things down, then yes, I'd agree that having the extra check is helpful. When you re-create an argument or diagram on paper you force yourself to work out the wrinkles and pay attention to the details in a way that you never do if you're just staring at a slide. However, not all lectures work that way unless you consistently take classes below your level. Sometimes you get hung up on a concept and you're forced to do two things at once:
1) copy the text & diagrams verbatim
2) understand the material
where #1 is significantly more cognitively demanding than reproducing an argument that you already understand (unless you have photographic memory, you look back and forth and back and forth) to the point that it inhibits #2, which creates a further need for #1 in a spiral of uninterrupted misery and needless failure.
This is where premade notes shine. They don't have to be a .ppt (I'd prefer if they were TeX sheets or a book chapter, assuming the book chapter actually corresponds to the same material) but they have to be there if you want students to be able to occasionally focus 100% on what you're saying.
Looking back on my LiveScribe archive, I notice a paradoxical trend: I took significantly better notes in classes that had support from solid permanent materials. Why? Because I was able to stop taking notes, focus, and fill things in later when appropriate as opposed to trying and failing to do #1 and #2 at the same time.