Growing up in the midwest with a basement, floods scared the bejeebers out of me. Most often our basement flooded because the sump pump overflowed. One of these babies would have saved a lot of our stuff! My Dad uses them now around his aquariums :)
All my stuff got flooded once and I'm more than willing to pop for one (or three!) of these to help prevent disaster from striking again. I can stick one in the basement by the hot water heater that should have died 6 years ago. I can put one in the bathroom as an added defense against my daughter's letting the tub overflow. I can put another by the aquarium...