Since the convention for mesh models is that the vertices, not the midpoints, represents the curve I don’t know if such a feature is suitable. Trimble must have though about it when adding the feature for the Polygon Tool and come to the conclusion to not add it to this tool.
The only reason to break the convention of letting vertices represent the curve is as a work-around for Offset and Follow Me which don’t honor curves but I’d rather have those tools corrected than Circle tools changed to allow for the workaround.