So it is said that if you know your enemies and know yourself,
you can win a hundred battles without a single loss.
If you only know yourself, but not your opponent, you may win or may lose.
If you know neither yourself nor your enemy, you will always endanger yourself.-Sun Tzu
Damn these books are EXPENSIVE for what you get.-Beowulf
Seriously though, SD nailed the reason and is why I collected nearly all of the original Journeybooks and supplements from the OR era SBG. They were very fun to browse thru, scenarios and terrain/painting guides were nice, but having the information available was the most important thing. If you're newish to the hobby and don't already have most of the (usually still current) profile information scattered across older books and PDFs then having the new books to better understand all you may face, as well as what you may want to field, is very important. If you already have most of the info (as some of us do) and don't have the extra money to play with (as many of us don't) then it's not as easy of a decision.