As you've probably noticed, I tend to use light weights during my workouts at the gym. Here I am today with 12 pound dumbbells -- a light weight by anyone's estimation.
Even so, I have definitely seen results. I can focus more on form and the mind-muscle connection. Also, by using lighter weights I can really target the muscle without other muscles jumping in unconsciously to compensate. My first priority, of course, is safety. If you're older, it pays to go light as your body will be more prone to injury and will recover more slowly from any injuries. If you already have this in place, then a reliance on lighter weights should diminish but not be abandoned completely.
Keep building muscle safely, my friend!