That looks really awesome. I would love one of those one day, but it's hard to justify spending +700€ for something that will only be strapped at torso (or similar), not being used as a dive computer.
But thanks for giving the first real answer to my question
I've a suspicion by the time you've figured out how to hook up that data logger and overlay its reading on the footage, the cost won't be too far from 700€. However as I recall from reading their manuals, it's not clear if they actually log the readings (there's an app to show them in the process but no fine detail is provided). i THINK @kelemvor has one of them, he might know.