Baumann's knife scrapings and forest animal pictures aside, there's nothing wrong with advising amateurs or people making art as a hobby to use cheap materials. Most of that hobby art will never be seen by anyone, and will eventually be discarded, so the materials don't have to stand the test of time. And I would hazard a guess that most of Baumann's audience are hobbyists. Nothing wrong with that.
But for what it's worth,
even hobbyists will have a better time when they use better materials. About 15 years ago I wanted to learn how to paint with hand-ground Chinese ink, so I bought a good inkstone and good traditional wolf hair brushes, but for some reason, I cheaped out on ink sticks. Well, not for "some reason," I did it because
high-quality ink sticks are expensive.
But the cheap ink sticks took forever to grind out, and the resulting ink was thin, watery crap. It was awful. I almost gave up, but then I figured I'd try a quality ink stick before throwing in the towel, and the difference was astounding. The quality stick ground out to a thick, dark ink that seemed to
interact with the paper rather than sitting on top of it or completely soaking into it.
Of course, the quality ink stick cost me about 25 times more than a cheap stick. But it made learning that process so much more enjoyable.