I would say that justice, in and of itself, is complicated.
Back to your scenario, the choice would have to be an informed one. Take, for example, an accused who is in a vulnerable situation. It's a bit like a sick person in a hospital. I am not a lawyer and I can tell you that going to court is pretty intimidating for those of us who aren't lawyers. Someone might feel at ease expressing themselves in their second language, but not necessarily using the right terminology. It is possible to make an informed choice at the beginning of the process, but that choice might also be a difficult one for an accused who is in a vulnerable situation.