"Important" depends on your POV
What you consider "important" will depend on your point of view. The nice thing that CBJN gives you is a rundown of all the different joints, what the rules are they're playing, and most importantly (even to a basic-strat-only player) the house edge.
So a quick glance at the Jan 2004 CBJN shows us that Bally's, as of last report, has 18 tables playing single-deck 6:5 payout, the pen, and so forth all equalling the house edge of 1.45- but it also shows their double-deck games (house edge .40), their 6-deck games (house edge .33), and their 8 deck games (house edge .56).
If your plan is to go and have a good time and play perfect BS and not worry too much about the rest, naw, you don't need CBJN.
If you wanna go and have the best shot at winding up a winner, or at least losing as little as possible, then yeah, you probably could use a copy of CBJN. It'll show you which games to play, where, and why.
I did a quick scan of CBJN and didn't see anywhere doing 6:5 payout on multi-deck games. Doesn't matter, it's such a horrible deal that you shouldn't play it on ANY game, and you should badmouth it as much as possible, IMO.
Coop