What makes the Joker in 'Batman: The Man Who Laughs' a compelling villain?

The Joker in this story is compelling because he represents pure, unadulterated chaos. He's intelligent, unpredictable, and revels in the suffering of others. The story carefully establishes his ruthlessness and willingness to commit horrific acts to push Batman's limits, making him an effective and terrifying antagonist who is difficult to predict or contain.