Yes, that - IMO - is the only real advantage. And, if the bass was a string-thru with a body made of, say, basswood? That's the way I would string it; optional or not...This is exactly how I've always thought of the thru-body option and its main benefit. From the structural standpoint, I like the idea of the pulling weight of the strings being supported by the body itself instead of all the stress being on the screws holding the bridge in place.
No perceivable improvement or significant difference either in terms of tonal quality or stiffness/flexibility otherwise.