It is common practice in the criminal courts to require written submissions, not only at the end of the evidence in judge alone cases, but also in respect of various evidentiary motions, or pre-charge discussions held before or during trial. In those cases, written argument is used, not in lieu of oral argument, but in addition to and usually as a precursor to oral argument.
If a trial judge requires arguments to be made by written submissions, the trial judge must allow counsel, after written argument has been exchanged, to make oral arguments in the presence of the accused to supplement, correct, or otherwise amplify the written argument. Procedural fairness and the accused’s right to be present throughout his/her trial require this. [FN]
R. v. McDonald, 2018 ONCA 369, at paras. 46, 47.
Counsel, however, may agree to waive oral argument either entirely or as a supplement to written argument.
Ibid., at para 46.
[FN]: Section 650 of the Criminal Code gives the accused the right to be present in court during the whole of his trial subject to exceptions. Closing arguments are part of an accused’s trial. Procedural fairness speaks to the principle that persons affected by the proceedings should have the opportunity: (i) to present their case fully and fairly, and (ii) have any decision affecting their rights, interests, or privileges made using a fair, impartial and open process: see Baker v. Canada (Minister of Citizenship & Immigration),  2 S.C.R. 817.