TBH, I've had a few of the things and the only 2 that have stayed dry are an old Canon D10 and an action cam (GoPro clone) that came from 7dayshop with a 30m waterproof housing. I've actually got 3 of the latter now - just in case the first succumbs to water ingress. I also use the action cams for time lapse videos of sunsets and bike rides. Barrel distortion is... noticeable (!) but not so much when you're close to the subject.
BTW, Mrs Nod uses one of the new fangled unicorn style mask/snorkels and can mount a GoPro (or clone) to the snorkel to get PoV video. Doesn't work for me - the beard prevents a decent seal!