Getting certification means you have had a third-party verified assessment of the impact of your business - your operations, the services you provide, the products you sell. So you understand that environmental impact, and you understand where those emissions are actually coming from, which lets you take a much more targeted approach to carbon reduction.
Achieving net zero is not something that happens overnight; it requires a comprehensive and detailed way to get there. Understanding what the footprint is, is one aspect. Understanding what actually drives that footprint is another. Breaking it down into a detailed report that highlights all of the emissions drivers in the business, and what can be done about them, is what makes for a much more successful journey to net zero.