Probably to stop the personality. Coups are often driven by "soldiers loyal to...". Having a civilian in the role would pre-empt that. OTOH a waiver undoes all

Probably to stop the personality. Coups are often driven by "soldiers loyal to...". Having a civilian in the role would pre-empt that. OTOH a waiver undoes all of that. It shows how much of democracy depends on people following conventions and traditions.