The true nature of sun gets distorted due to the presence of clouds. The Shastras say that one has to go beyond the intellect to understand one's true nature. Examples such as the snake and the rope is an illustration so that we can understand the Advaitic Concept within our intellect. Shankara knows the limitations of examples and limitations the intellect. The answer is quite simple.
Faith is another important input to go beyond the intellect.
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