Use Case
The liberty-maven-plugin has a debug goal which allows you to start the server in debug mode, but in the foreground.
Often when wanting to attach the debugger, this is all you'd need. You can execute tests separately somehow or via other goals launched from another shell.
But the debug goal, like the run goal, runs in the foreground and blocks until the server process completes.
If I want to continue to the next phase of my build, e.g. on to run integration tests, it could help to configure a start goal to start the server in debug mode, in the background, and continue on.