Most lawyers don't bother to write. They just do their jobs or bill their hours. You, however, take an interest in a topic, research it exhaustively, and provide valuable scholarship on that topic. You make yourself an expert, and in doing so, make a valuable addition to the collective knowledge of our trade. Remarkably, you share this work publicly and for free, on firm blogs, discussion forums, or journals.
In short, you elevate yourself and your profession. You are exactly the kind of lawyer we're looking for.