Quick, which is more dangerous around a child: a loaded handgun, or a swimming pool?
The fact that I ask it that way should clue you in to the fact that it's actually the swimming pool, which kills literally hundreds of children under 5 every year. That's where the safety turtle comes in. It's an alarm that goes off the instant a child (or even a pet) hits the water, providing a vital last-ditch level of protection for your kid.
If only they'd figure out how to make one that'd catch a cat wizzing on a wall...