A page of fields is easy to miss one of. A signer scrolls, fills the obvious signature, and leaves a date or a checkbox blank because it was further down the page.
Signing walks through the fields in order. The signer moves from field to field instead of hunting for the next empty box. Each required stop is part of the pass.
After the fields are filled, they review the document before it is finished. The review is the last look at the whole agreement, with the values in place. The document is not completed until that review is done.
The path is fill, then review, then finish. A signer is not dropped on a long page and asked to notice every field on their own.
