What knot is recognized as being less efficient than the bowline on bight and square knot?

The running bowline is considered less efficient than the bowline on a bight and square knot primarily due to its structural integrity and ease of untying. The running bowline creates a loop that can slip under load, making it less secure in various rigging applications where maintaining load integrity is crucial.

In contrast, the bowline on a bight provides a secure double loop that can withstand more tension without slipping, which is essential in situations where safety and precision are paramount, such as in rescue or sailing scenarios. The square knot, while often used to join two ropes, doesn't provide the same level of security or stability compared to bowline variants.

Other knots like the reef knot and figure eight knot also have specific uses but do not offer the same advantages in terms of reliability and security that the bowline on a bight achieves. The running bowline, while useful in some contexts, is thus recognized for its limitations in efficiency and safety when compared to the bowline on a bight.