The Best Practices patterns provide individuals with a tested, refined "bag of tricks" known to produce workable software. Many experienced developers will have discovered many of the patterns on their own, even if they haven't articulated them. Even for the most experienced, the Best Practices patterns will provide food for thought, and possibly even a platform for further exploration of the pattern form.
It is in group development that the Best Practices patterns really pay off. Groups use the patterns as a shorthand vocabulary with which to design systems. New developers can be taught the patterns to help integrate them with the existing systems. The patterns become a powerful documentation tool. As simple words and phrases take on rich meanings within the group, the patterns can convey in a few words both the structure and intent of the system.