To me, it would just state the obvious ...
But then again, I'm a bit of a **** and probably am missing the entire point to the book ...
Personally, I'd rather put the $20 bucks to new strings, save up for a new piece of gear ... something along those lines. Maybe a new outlet for my 400amp circuit I'm running for my 10,000watt amp in my new basement.
But I'm not a big reader. Puts me right out.