util.promisify transforms callback-based functions into promise-returning functions, streamlining asynchronous operations in Node.js. This utility simplifies asynchronous code, making it easier to handle errors and structure asynchronous logic using async/await. It's crucial for modernizing older Node.js APIs, promoting cleaner and more readable code by leveraging promises instead of callbacks for asynchronous flows. It enhances code maintainability and reduces callback hell, vital for robust applications.