Satoru Gojo covers his eyes primarily because of his powerful and rare ability called the "Six Eyes." This ability allows him incredibly detailed perception and the capacity to see cursed energy with extreme clarity. However, using Six Eyes constantly without covering his eyes causes extreme fatigue and rapidly drains his energy. The blindfold or other coverings help Gojo manage this energy drain and prevent sensory overload by limiting excessive visual information. Even with his eyes covered, Gojo can still effectively perceive cursed energy due to the nature of his ability, so the blindfold does not hinder his power. This strategy helps him maintain his strength and stamina during normal daily activities and combat when not needing to unleash his full power.