Not all values need to be defined. There are valid defaults for version (which defines the default version for a new project) and modelsFolder (which specifies the location of the models within the project folder) that usually need not to be overridden.
The file is picked-up per default. Parameters specified on the command-line override the values in the project settings.
Default POM Elements
The creation of a customized POM file for the new project contains typically organization and / or project specific elements. These can be provided in a base POM file that is located next to the project-settings.xml file. The name for this file that provides fragments for the project POM file is project-settings-pom.xml.