Process Builder allows administrators to automate business processes and workflows visually without code. It provides many advantages over traditional workflow rules, including the ability to create records, update related records, launch flows, submit records for approval, and post to Chatter. Process Builder can be used to automate tasks like populating fields, assigning ownership, and updating statuses. While powerful, it also has some limitations around editing processes, troubleshooting, and setting field values with formulas.