In my admittedly limited experience, there are other advantages to message catalogs. They not only allow easier multi-language solutions, and the potential for more complete docs. They make it easier to discuss the messages with the users. They also facilitate changing the messages. If the owning user wants to alter the text of a message, it can be changed in the catalog without changing the code. All of this is true even if you have only one language to support and you never get around to documenting the catalog.