A gulf ball may have dimples but it is still a sphere. The golf ball is not shaped like a cylinder or a disk. If a gulf ball had less air resistance shaped like a disk or a rod, they would make them that way. As someone else on the forum once pointed out, If you take a piece of tin foil and throw it, it hits a lot of air resistance and gets push back and slows down and does not go very far. If you crunch it down into a tight ball and throw it into the resistance of the air it goes a lot farther as it is just more efficient to overcome the air density or in the case of rigger weights, water resistance. That said the dimples on a ball can greatly increase its efficiency.
What happens with these long and flat weights is that in current, especially cross current to the direction of travel, the weight gets pushed by the cross current asymmetrically and turns somewhat to various degrees so that it presents a wider surface to the water it is being dragged into. Unless you have the need to side plane, I understand the sphere is more efficient overall.
To my way of thinking there are two reason to put a fin on a ball or make it elongated, One is to use the slightly curved fin to side plane the ball out away from the boat.
The other in theory with a short strong and straight fin or elongated ball is to resist the ball spinning on the swivel and increasing wear on that component of the terminal gear. In reality in my view the fin gets acted upon by a number of forces and tend to move back and forth and still puts wear on the swivel and perhaps less even wear than if it just spun slowly and evenly. The fins are almost never perfectly straight especially after it has spent much time on the boat. I think Scotty played around with a small plastic fin that went not on the ball but just above it on the terminal gear/cable, I think the theory was it could helped the cable resist the ball turning the cable and increasing cable metal fatigue by keeping the wear on the ball swivel below the little fin but not sure.