dev goal contains only name property, but not filename. name property is used also as a filename to deploy. It is impossible to deploy file with different runtime name.
deploy-only goal contains both name and filename. name is used as runtime name. Therefore, it is possible to deploy file with different runtime name.

This mismatch in goals makes difficult to use the same war file for aims of development and integration testing. Within integration test maven phase deploy-only goal is used and it is possible to set another runtime name (and context path) for application, but developers (with dev goal) are forced to use runtime name (and context path) which is coinciding with filename.