As I posted earlier, the benefit of cable steering is twofold. #1. You are in direct contact with the steering arm, so any slop or binding is obvious, and you're more likely to know when there is a problem in the steering system. And you'll know it before the boat ever leaves the trailer. #2. Cables only last 5-7 years before they begin to get so stiff that they have to be replaced, so you are forced to service the steering system before catastrophic failure like "total loss of control" happens.
I've seen stuff like batteries shifting and kinking a hydraulic steering hose, then when the steering wheel was turned the hose ruptured. Motor can now flop around freely with no control.
I've also replaced a system after a guys kid got in his boat while on the trailer and cranked the wheel while the motor was secured by the transom saver. It cleanly broke the flat cylinder mount. What if it had only cracked, and the kid never said anything??? Or how about the guy at Truman on a windy day whose boat drifted back into a tree, motor hits tree but hydraulic steering kept the motor from turning sideways... Something had to give, and it was the hydraulic cylinder bracket. If it had been Cable steering the motor would have been shoved sideways against the stops and nothing would have broken.
Sure it's great to be able to steer the motor with your pinky finger, but don't ignore the fact that the reason that is possible is because of the assisted torque of the hydraulics. I can lift my truck off the ground with one finger too if using a hydraulic jack. You don't think the same type of force can break a 3/8" bolt or a 3/16" plate of steel? I'm here to tell ya YES IT CAN.
You can hold the motor from turning with a cable system and you can't crank hard enough on the steering wheel to break anything. The connection between your hands and that motor is way more reliable and durable with cables.