I always understood that usage to mean that there are deeper, unexpected layers, not that the time spent is necessarily valuable. “Discover the lost art and sci

I always understood that usage to mean that there are deeper, unexpected layers, not that the time spent is necessarily valuable. “Discover the lost art and science of the London system” (in chess) would be a deep dive into it, rather than an explanation why playing it is a better use of your time than learning other openings.