I don't want to confuse you, so in case it's not apparent, this is not the boat that's in my signature line. This is another boat I have that I don't have any mod pics of on here. I don't want you trying to envision this setup with my current build in my sig.
The cooler just sits on the floor (specifically on the hull) not a "floor" of any kind. If you notice at the top of the pic, you'll see wood. I made a battery box in this boat that holds 2 deep cycle batteries for the front trolling motor. I made the box after buying the cooler, so I intentionally made the cooler tight sitting where it is between the middle bench and the battery box. The sides of the v-hull wedge the cooler in from the sides. The only reason I take the cooler out of the boat is to dump out any remaining water that the bilge leaves behind after a weigh-in, and when I want to scrub it out. Other than that, it stays in the boat and acts like a cooler as well as keeping my battery box in place. Because I also use the cooler as dry storage, I don't want anything I put in there stinking like fish, so being able to take the cooler out allows me to clean it more than most would I imagine.
That said, my new boat has a livewell that I built in. I have much more closed storage space in the new rig. I debated on going the same route with the cooler in the new rig, and I probably would have had I not found a livewell that fit (nearly perfect) inside my rear bench and the fact that the transom already had a hole for the fill pump. I'll also plan to have me and my 2 kids in the boat alot, and the cooler would have had to occupy some of the available floor space for whoever was in the middle.
To me, the cooler is just terribly easy, affordable, and convenient. No holes in the boat, one pump, and the pump was wired to a cig lighter adapter.