@f997373b @a604497f It's a very good question.
I would say, *especially* if it's the best one.
Here, there are good concurrent, but f they where none, the more the tool would be used, the more the project (the language) would be biased toward «be used with the tool». Which would be problematic for a Free tool that a programming language should be.

Furthermore, enslaving the exercice of your art to a commercial licence is not very safe. 

 @01006382 @a604497f Sooo, we must use bad and ugly software, that has less useful functionalities, and that sets back our productivity to... do what? Give some hope for community driven text editors to become full-grown IDEs someday in distant future?

You say that you don't loose time when using open-source apps, but I think you just justify yourself in that regard ;)