I'm skeptical this is a major breakthrough, and that the benefits will justify the cost. I'm used to the reality that total immersion will probably ruin electronics--been true for almost 100 years. When I take a camera kayaking I go for a cheap one (which an immersible one probably wouldn't be).

However, I did have one major regret, with an electronic car key. I had a very scary moment where it did not look like I'd be able to disarm the car security system and drive home, before I found the spare. These are hideously overpriced to start with, and have to be programmed by the dealer. I don't imagine you'd notice the increase in cost if they were waterproofed.