I never use the Languages tab of the Publish dialog, because those fields (Publish string set included) are only applied if you specify a translation file in the first field.
Our translation process is by chapter, so I can’t publish using just one translation file. For example my title has 24 chapters, so I create a copy of my title, export/translate/import each chapter, and publish with the relevant publish strings. There is also post translation editing required, to re-format where wording is longer, and also any images that I’ve placed into text captions have always been moved so I have to go and put those in etc.
For very small titles I suppose the single file option would be useful. This is how I’ve been working so far, and of course I may be missing something, so if you know of a better way, I’d love to know about it!