There are a lot of 12 volt parasitic loads. Some you can find and shut off, like the booster on a bat wing antenna. But other 12 volt loads, like the electronics for a refrigerator, and carbon monoxide detector, maybe electronics for heating and cooling, and even an inverter is you have one, really require a battery disconnect switch.
I only have one battery. I can come in off the road with the battery fully charged from 3 days driving on the interstate. Then, if I forget to flip the disconnect when I put it in storage, my battery won't have enough juice to open a slide out in just one day, maybe two.
I would look hard and long for a place to conveniently locate a disconnect switch.
