“The complete saying was originally “A jack of all trades is a master of none, but oftentimes better than a master of one.” Formerly intended as a compliment, the phrase means that a person is a generalist rather than a specialist, versatile and adept at many things.”

This is the problem with our habit of shortening things. We don’t understand their original intention anymore. We shouldn’t ignore the old adage but the new one (in this case, at least).