Often objects will be positioned by State Vector. A common case would be a Spacecraft simulating physics in Unreal Engine’s Rigidbody Physics system. E.g., the positioning calculations run the “reverse” direction: the state vector is known but orbital elements are not.
Computing orbital elements can also be useful for objects positioned via Ephemerides or TLE data.
Orbital elements are easily converted into conic sections that can be rendered (ellipse, hyperbola, etc). It is much easier to render a conic section based on orbital elements than an actual trajectory from an Ephemeris or TLE.