Most things that you can do manually in the browser can be done using Puppeteer! Here are a few examples to get you started:

Generate screenshots and PDFs of pages.
Crawl a SPA (Single-Page Application) and generate pre-rendered content (i.e. "SSR" (Server-Side Rendering)).
Automate form submission, UI testing, keyboard input, etc.
Create an up-to-date, automated testing environment. Run your tests directly in the latest version of Chrome using the latest JavaScript and browser features.
Capture a timeline trace of your site to help diagnose performance issues.
Test Chrome Extensions.