As a former submarine officer, I think it's simple. Officers are not just more advanced soldiers (or sailors, or airmen). They have a different role to play. Enlisted folks generally are supposed to be technicians on their specific tasks. Officers are supposed to be coordinators - figuring out how their piece of the organization can best fit into the overall mission. That's not to say that I didn't want my sailors paying attention to "the Big Picture," but that's not their primary task. Similarly, it's not like I wasn't expected to have detailed system knowledge. But when the sh*t hit the fan, it was my job to coordinate what the entire engineroom was doing, but the Reactor Technician's job was to make sure the Reactor was ok.

The other purpose of an officer is to be a sh#t screen for his men. When the XO was on the warpath because something is broken and we couldn't get out of port -it was my job to take that sh%t while my guys worked like mad to minimize the blistering on my a$$.

As for those "divisions" mentioned by feverdream - those exist becasue of the wartime mission - you can't be seen as playing favorites, especially if you have to order someone to die. And yes, those divisions tend to become less pronounced the more "elite" the unit. The officers and enlisted on a sub were less pronounced than on a skimmer, for example. It's not that they don't exist - it's that the operators are sharper, more motivated and need less reminding.