Using a slow cooker for this dish allows all the ingredients, including the chicken, tomatoes, spices, and rice, to meld together over an extended period. The low and slow cooking process helps in developing deep and rich flavors as the ingredients have more time to infuse with each other. The gentle heat also ensures that the chicken becomes tender and juicy while absorbing all the seasonings from the broth. This results in a well-rounded flavor profile that is hard to achieve with traditional cooking methods like stovetop or oven cooking.