Honour guards are human. They weren't designed and built by an arms manufacturer.
Do you get "purely ceremonial" tanks?
A freighter can not be built for combat because its primary role is transporting cargo. A shuttle can not be designed for combat because it's primary role is transporting people. But all a starfighter does is fight. How can you have a starfighter for which the primary role is not starfighting?
Utilitarian design can be to a degree, not absolute.
"Heavy" and "super-heavy" tanks and Battleships, particularly around the time of WW2, were more often icons of national pride than entirely practical designs. While they are certainly combat-useful, logistical and strategic concerns make them poor choices on which to spend excessive resources. If you have some know-how, it is probably possible to point at any category of military equipment and find examples that were designed without maximum practicality in mind (excluding examples of "practical" designs simply failing to perform).