My friend played Elite Dangerous and he loved it, so if you want to get it, you should. But to answer your question, i never really thought of it like that. It's a pretty creative idea to us if you're writing Sc-fi.
I can think of a few reasons why it would be best to make it in a more aerodynamic shape, although the viability varies on the specifics of the universe you're writing in. For a warship, an aerodynamic ship presents a smaller attack surface. Enemy missiles may have a harder time hitting a thin cylinder pointing in the direction of the missiles than a bulky cube, and missiles won't be able to turn on a dime to face the side of the vessel. When moving at fast speeds, a micrometeorite or similar small piece of debris can really ruin your day. A smaller ship will have a smaller chance of hitting such an object. Aesthetically pleasing ships are easier to convince politicians to build, and enemies to be afraid of. An aerodynamic ship may be more difficult for enemy radar (or equivalent) to detect. The physics of your propulsion method may rely on a shape, such as in David Weber's Honorverse series.
