Hypocrisy is not always an empty criticism, but you have picked an example that is. Someone who smokes saying "smoking is bad for you" is not a serious hypocrisy -- it could actually be informed wisdom, and they are just stating a fact. Someone in a position of power or influence who smokes on a regular basis, yet would form laws or prosecute/punish others for doing so, is a much better example of when hypocrisy is not at all an empty criticism.