Your dog's name matters to him.
Dog experts say dogs live in a sea of human sounds and have the language ability of a two-year-old, so he has to figure out which words are directed at him and which aren't.
Dogs understand you're talking to them if you're looking them in the eye, but if you're not, the grammar you use and when you say your dog's name is actually important for him to understand what you're telling him.
For example, saying "Sit, Rover," is not as effective as saying "Rover, sit!" because saying his name first gives him the signal that the next words out of your mouth call for him to respond.