As someone with an anomalous heart condition (Brugada Syndrome - BrS - or sudden unexplained nocturnal death syndrome - scary, I know) I can say that I would never just rely on a cheap device sensing in an unreliable position. When I go for checkups the monitors they use are located on my chest and far more reliable. I will keep an eye out, though, as if the monitors do become more reliable I may go for one just as an added check. Perhaps, and it's a big perhaps, once could have saved my uncle who died as a result of BrS.