Well your idea will be fine for 2 languages. When you make soft modifications, you pay double price.
For more than 2 languages, the work becomes outstanding.
One idea with the text file is that if there is a message or label error (which can happen when there are many languages), you can correct it without making a new build.
Furthermore, some of our customers can implement themselves new tongues by asking translators to do the job only in the text file, which is easier