I believe that it is good to practice all techniques and mix them up as well. When you need to play smooth détaché, you should practice working on the smoothest possible bow changes and when you need to emphasize each note, you can work on martelé.
That is not to say that it would be harmful to use the intended pieces for practice that will help you with another type of technique
It's more important, however, to focus on what you want to achieve in the end.