Let us say that, in a given region, there are no francophone judges available. What can you do in that case? Some people will decide to proceed in English.
In my criminal law practice, I had an accused ask me whether the judge would treat him more harshly if he asked for his trial to be held in French. We obviously want to avoid this perception.
The issue of delays is extremely important, even in criminal cases. For accused persons in jail waiting for their trial, it is unpleasant to have to wait a number of months before their cases are heard.
There are other problematic situations. For example, I heard some of my colleagues from southern Manitoba say that some counsels knew that a certain francophone judge was stricter towards the accused. They would therefore specifically ask for the trial to be conducted in the other official language so as not to have their case heard by that judge.
To answer your question, I must say that there are many factors to consider. I do not know whether my colleague Mr. Rémillard will want to comment on this.