Your bookkeeping staff can benefit from having someone who understands the business able to advise on how best to account for certain situations.
Whether it is as simple as how a journal should be posted or more complicated such as the correct accounting treatment for a financed asset it can help to have someone on hand to advise who understands your business.
Liken provide a fully qualified resource to help support your accounting function - more adaptable and better able to understand the commercial requirements of your business than a typical firm of accountants.