Once upon a time bilge pumps were wired to a breaker switch in the 12V side of the panel. When you came aboard you would switch it on to discharge all the water that may have accumulated since the last pump out. When done you would turn it off and then switch it on and off a couple of times during the outing and a final time before leaving the boat. Someone got lazier and came up with a float switch that would automatically turn on the pump whether they were aboard or not. To avoid the discomfort of those that did not feel confident leaving the 12V panel ON the hard wiring of the pumps directly to the batteries was incorporated. Not soon after, since human intervention was no longer necessary, people forgot about the pump and maintenance fell by the wayside; many batteries went dead due to faulty float switches and pumps that had failed were only discovered when water came up the floor boards. It is still thought by many that having an active bilge pump when the boat is unoccupied is safety consideration that will help prevent a boat from sinking (myth). In real life the output of the average bilge pump is about 20% of its rated capacity in GPH (do the math) and even a small water intrusion will overwhelm the pump that was merely designed for convenience. Getting on the knees to scoop incidental water out of the bilge got old real quick so the electric bilge pump was and is a great help. My point is that if you feel more comfortable turning Off your battery switch(s) go ahead and do it irrespective of how your bilge pump is wired.