The reason why I can’t do as you suggest is because enabling that option severs the link between the ACF taxonomy field and the data it’s trying to store.
From what I’ve seen in ACF5, when this option is enabled and I select “Toronto” from the “Born” dropdown, two things happen. First, “Toronto” is assigned to the post as a tag (or in my case as a custom taxonomy term) and second, the “Born” dropdown reverts to default (meaning “Toronto” no longer appears in the “born” dropdown).
So no, this isn’t a realistic solution, which is why I’m doing what I’m doing.
