If you’re really not intending to animate or re-pose your character, then I would say an armature, etc, is really just an added complication. Armatures and rigging are for animation. If you are just making a sculpture or a rendered still, you will probably have more control if you just model the position exactly as you want it.
If you want the freedom to adjust your character’s pose after modeling, then you need to rig it. So it all depends what you want to do. Do you want a puppet, or do you want a marble statue?
Also, if you’re modeling just for a still, and you know exactly what the framing will be, then you’re better off just modeling the part that will be rendered. Basically, all modeling and rigging and armature creation is work. Don’t do work you don’t need to do.