It is pretty cool until you realize how much easier it is to spy on a combination than stealing a key from a somewhat careful person. Note that I am not trying

It is pretty cool until you realize how much easier it is to spy on a combination than stealing a key from a somewhat careful person. Note that I am not trying to imply that stealing a key is hard or anything. It is in fact quite easy. But at least for me, I need my keys every few hours, so even if you managed to steal my keys from me without me noticing the theft, I would still know that my keys are gone at most a few hours later and 1 or 2 hours later, I'd be convinced that they are stolen. Thus, your window of opportunity is just around a few hours. If you just spy on the combination, you know the combination and the window of opportunity to break into the house is as large as the frequency of combination-changes. which, considering password-changing-frequencies in real life, might be month to years. Thus, I don't really think the coolness offsets the security issues.