Personally, I don't think they're all that important. Come to think about it, I don't think I've ever consciously applied them when I improvise. Maybe I do it subconsciously, don't know.
The theory behind them is so that you land on the chord tones on strong beats but I don't know that that's important or even desirable. I think they're good to have under your fingers and they're good to know if you want to play conservatively.
I don't know the Black book but David Baker's got one that covers it pretty well.
(edit - looks like your finger is a little quicker than mine, Clayton.
)
The theory behind them is so that you land on the chord tones on strong beats but I don't know that that's important or even desirable. I think they're good to have under your fingers and they're good to know if you want to play conservatively.
I don't know the Black book but David Baker's got one that covers it pretty well.
(edit - looks like your finger is a little quicker than mine, Clayton.