The benefits are myriad: a massive, wall-to soundstage, and within that, excellent image focus and layering, a strong and detailed center image, less room interaction, and greater sound pressure levels without room overload on account of the minimal distance between speaker and listener.  

The trick to making it work is to ensure that the speakers lend themselves well to close listening distances.  Generally, speakers with first-order crossovers and multiple, largely-spaced drivers are less successful, but even then, there are exceptions (Dynaudio comes to mind).  It helps, too, if the speakers can be placed relatively far into the room (e.g, four feet or more).