Is there a product for channeling water away from water appliances?
Water heaters have pans. You place the pan under the water heater, then attach a hose to send the water someplace less damaging.

You can also get water sensors, which rest on the floor and sound an alarm if water is detected.

There's less stuff for dishwashers and washing machines, as they only contain water when in use, and there should be someone nearby when in use. Water heaters are commonly left alone for weeks on end, which gives more time for a small leak to turn into something damaging.