Actually, I don't think much of the way the "sword" frequently is used in Aikido. In my opinion, it all too often leads to an almost limitlessly stupid self-overestimation, because in reality you wouldn't have the slightest chance against a good swordsman.
Could the "Randori" with several sword-wielding partners not simply be a holdover from the pre-war and wartime periods impregnated by propaganda ... ?
However, as a pure teaching aid to evoke certain reactions and to explain movement principles in Aikido, the use of a bokken can still be quite useful. However, this should in no way lead to the belief that one can easily disarm anyone as a matter of routine or that one is in any way equal to or even superior to an armed person through one's own knowledge of Aikido.
I don't know your examination system, but I could still imagine that a second partner behind the examinee with his Bokken has the task of forcing the examinee to do a really good Irimi, for example.
Of course, I would estimate my (or most of our) odds against a skilled swordsman as almost as low as the odds of being set upon by a skilled swordsman in the first place.
But instilling and demonstrating situational awareness of an/other attacker(s) is as good a rationale as any I might come up with. I'll process it through that perspective. Thanks!