One advantage or learning by translation is that you can figure out the parts in language that you already know which are missing in the new language. That way you can modify the new language you are learning to suit your needs. Instead of being limited by the limitations of the new language.

For a lot of professionals, this is excellent because they can seamlessly now move between languages without having to translate concepts.

I'm on my 6th language now and most language teachers are absolutely horrid having no sense of how to teach.