Steel tube couplers contribute to the overall durability and longevity of a scaffolding structure by providing secure connections between the steel tubes. These couplers ensure that the scaffolding remains stable and strong, even under heavy loads and adverse weather conditions. They effectively distribute the weight and forces throughout the structure, preventing any weak points or potential failures. Additionally, steel tube couplers are resistant to corrosion and wear, improving the lifespan of the scaffolding while maintaining its structural integrity.