He values secret identity and protects it more than anything, and so for a character to repeat this name, who isn't a family member or a close friend, it places power over Bruce: "Are you so sure, Bruce?" "Not this killer, Bruce." It's something intimate. Orlando and Snyder do something interesting here, by showing that The Shadow knows Bruce Wayne, they immediately create a connection and bond. After all, how many people in Batman's life knows his secret identity and not form a strong relationship with him (including evil, toxic relationships). In addition, The Shadow is a character that kills, they're both vigilantes, but that's a major difference. It looks like a slow burn, from distrust to possibly trust? It feels like their relationship is going to be a slow burn. It'll take a few tries to gain Batman's complete trust, and the Shadow does not accomplish this by the end of this