I've searched around for other videos and this appears to be the only one out there so far. I'd want to see this repeated (several) times and get a visual confirmation on the water damage indicators Apple has included in each of its iPhone models since generation 1.

I'd also want to see if those phones worked a week or two after the test to ensure that their insides didn't corrode after their submersion and subsequent exposure to air.

If this is indeed waterproof, I'd also want to know about how deep it can go.