Relaxed fit cycling pants are ideal when comfort over long hours matters more than aerodynamics. If you're planning endurance rides, multi-day tours, or bikepacking adventures, the more generous cut reduces restriction and lets you shift positions on the saddle without fighting your clothing. The slightly looser fabric also allows more airflow, which helps on hot days.
The trade-off is a small aerodynamic penalty and less muscle compression compared to race or club fits. You won't get that second-skin feel, but you also won't feel squeezed after hour four. Relaxed fit is also great for riders who simply prefer less restrictive clothing or who find tighter fits uncomfortable.
One thing to keep in mind: relaxed doesn't mean baggy. The pants should still follow your body contours without excess fabric bunching up, which can cause chafing. If you're between sizes, stick with your normal size rather than sizing up for extra room.