Process creates clarity – everyone understands exactly what is expected of them and others. They know when it's expected and they know how their step in the process contributes to the overall outcome.
Process creates alignment – People see the bigger picture.
Process avoids human error – without a clear checklist of items, things will get missed. People are forgetful, uncommunicative, tired and busy. Having something written puts checks and balances on human error.
Process creates replicable results – doing something the same standardized way means that you ensure a benchmark of quality. The same input will create the same output.
Process gets better over time – as you run through a process, you'll see ways things break. You'll find edge cases, weak links, and outdated reasoning. Having a clear process is antifragile – you can update it based on what you've learned. Those updates will create compounding positive results.
Process empowers people to learn – when you add someone new to the organization, having a clear process to follow will empower them to quickly learn every step by following the clear instructions. It will also give them a safety net as they try things for the first time.
Process empowers people to focus – instead of needing to worry about managing the entire task and recruiting help, process allows you to focus on the small section you're concerned with right now. This allows you to think deeply and be creative in how you solve that one piece of the puzzle.
Process avoids blame – if something goes wrong, its nobody's fault. It just means that the process needs to be updated.
Process is scalable – Imagine if every car on planet earth was made by one person each. There would be almost no cars on the road. By having clearly defined process, you can add many more highly specialized people to the problem and scale the output.