Lighting can be as simple or as complex as you make it. As someone who uses light meters myself, I struggle to articulate why using this handy tool can be a far more efficient way to light a scene. In this informative video, the simplicity of lighting a portrait using ratios is explained far better than I ever could!
Ratios of light have been used to describe the way light hits a subject far before photography was invented, but photographers have used the idea of ratios to predictably and consistently create certain looks in their creations. Using a light meter, the photographer measures the amount of light falling on each side of the subject, adjusting the power of the light or settings on the camera until the desired look is attained. So, why not just chimp at a shot and light to taste? There's absolutely nothing wrong with that! However, to really dial in the light for consistency and speed, using a meter can be far quicker and more efficient. You can light a scene before your subject even steps on a set if you're using a light meter. If you're chimping, you need to wait for your subject or stand-in to begin. For simple incident lighting, I use a Sekonic 308 Flashmate, but used meters can be found cheaply as well!
I would equate lighting a scene by meter to using a recipe to cook as opposed to taking a "add a pinch of this, a dash of that" type of approach. Both are completely valid and can produce fantastic results. The recipe, however, is far more consistent and predictable. Check out the video and see some simple ratios in use, then maybe try to incorporate some metering in your next shoot!