They are very useful! Still not perfect, of course - they must be kept full of energy, and they require access to a...signal.

[please don't ask him to explain this]

I know how to use mine well enough, but that is about all. I hear that the newer ones can show you the person you are talking to, as if you were right there with them! [Okay, he does understand it a little better than that by virtue of knowing what TVs are, but referencing television will not help here.]