I may be the only person left on earth who used to read the manual cover to cover, and the Cakewalk manuals were among the few that were worth reading. The thing is, I would typically read them when I was stuck somewhere, and not at my computer trying to get something done, and I do not own an e-reader (too small, content way too expensive considering the cost of publication, and too intrusive, sending back to third parties not only what I am reading but which page and for how long) so that stopped when the manual became pdf only. That is still a major advance over Microsoft, which stopped even making pdf manuals for their software when they found out how to screw their customers with Microsoft Press.
There may not be anything in Scott's book that is not covered in the manual, and not all of it is necessarily all that much simpler to understand than the manual if you are a technically sophisticated reader, but it is portable and on paper. And some of it does explicate some arcane points better than the excellent pdf manual that comes with Sonar. If your kindle is on the blink, or if the pdf manual leaves you cold, or seems to be written in a foreign language, you can certainly benefit from the book.