Suppose we have a multimodule which results in a war. In the end we want to run this war in a container like jetty. Up until now the jetty:run is executed on every module, which doesn't make sense for the other modules.
This is just one of several examples where you want to control on which module to execute a specific goal. In case of wars, the plugin could check for the packaging type, but in case of jars this won't work.
There should be a generic solution to mark goals for a specific module.