That was a hard question. Narrative is great because you just read along and the author explains it all as he goes; sort of like the narrator for all those wonderful National Geographic films about whales, penguins, jungles and such. The image is projected into your mind's eye and as you read, it is like a movie.
But the reality is simple. Dialog is a part of your character. Unless they are mute, your characters have to communicate -- so, in reality, if they were mute, they'd still communicate through signs and actions.
As a reader, any writer who can give convincing dialog without all the daily mundane sounds "How are you?" can make the story move along very nicely. When I write my first pass, I basically tell the story using dialog.
My friend, an alpha-reader for my rough first passes, brought it to my attention through a very unique description. He said: Reading your stories is like listening to a stage production prior to dress rehearsal and the addition of props. It is interesting but I only get to hear about the action. I want to see the action, know the colors and feel the wind on my face.
I have found narrative interesting but sometimes I feel the characters are lacking due to very little conversation skills on their behalf.
In literal narrative, you'd read 'The sheriff wanted more details. The young deputy drove out to the house and called back to the office to tell the sheriff he'd spoken with Cooter, learning about Mr. Wilson's involvement.
While with dialog you'd get something like The sheriff wanted more details. Deputy Wade Hall pulled up to the dilapidated house. An old man sat rocking in his chair on the porch. "So, Cooter, did you see that young girl or not?" The young deputy eyed the old man suspiciously. "If'n y'all done come earlier-" Cooter leaned over, spit and hit the tin-can spittoon with dead-on accuracy. "You'd see'd her with ol' man Wilson from the dime-store." Cooter pointed at the kudzu entwined trees beyond the fence. "The two of dem were wandering back in dem woods." The deputy nodded and headed back to the car to let the sheriff know about Wilson's strange involvement.
By using dialog you were able to make Cooter a character and give some flavor of the locale - obviously in the South since kudzu hasn't quite made it to the North... yet.
So, personally, I love dialog and do most of my first-pass writing with dialog then go back and add the ambiance of descriptions, personalities, etc. In other words - I create dress rehearsal. You can do the same - add dialog to your story which will help describe what/where/why while at the same time, move the story along.