The dependency management section is a mechanism for centralizing dependency information. When you have a set of projects that inherit a common parent it's possible to put all information about the dependency in the common POM and have simpler references to the artifacts in the child POMs.
I see the benefit to depend on very same artifacts in many different maven projects (having just 1 bundle might be common, but I know many projects with more than 1 project bundle).
The dependency management section is a mechanism for centralizing dependency information. When you have a set of projects that inherit a common parent it's possible to put all information about the dependency in the common POM and have simpler references to the artifacts in the child POMs.