1. Binding can increase the stability of the ladder. If the ladder is not tied, when someone stands on the ladder, the ladder will tilt or shake unevenly, increasing the risk of falling. By binding, all parts of the ladder can be fixed together, making the whole ladder more stable.

2. Binding can protect the ladder. If the ladder is not tied, when someone stands on it, it will be accidentally damaged. By binding, all parts of the ladder can be fixed together, thus protecting the ladder from damage.