What is the significance of Lady Macbeth's speech in Macbeth?

Lady Macbeth's speech contains a variety of techniques used to elucidate her descent into madness. We can see this when she states: "out, damn spot, out!". Shakespeare's utilisation of repetition highlights the overwhelming anger and fear Lady Macbeth is experiencing, and this is further supported by the reality that the spot does not exist, juxtaposing Lady Macbeth's wild and erratic fantasies. Moreover, the symbolism of the spot as an antithesis to Lady Macbeth's evil nature can be said to be symbolic of King Duncan, whom she wanted dead in order to fulfil her desires for power and wealth. Contextually, Shakespeare's portrayal of Lady Macbeth as the dominant force in her marriage to Macbeth would have critiqued and contradicted the stereotypical Jacobean image of women as housewives and overall submissive to their husbands. Shakespeare does this to examine this stereotype and challenge it, in order to interest and engage viewers.