Every business has confidential information it needs protected, information such as salary reports, profit projections and forecasts, performance reviews, marketing strategies and customer lists. In many cases, it is better to let your Excel expert safeguard that information. This person is unbiased and has no stake in the company. Additionally, he will never share the information with anyone the company says can't see it.
There are many reasons why having an outside person safeguard your company's information. Maybe you run quarterly metrics that determine employees' bonuses. A third party maintains confidentiality, thereby eliminating staff infighting and jealousy that could come when people see the data before you're ready to show it.
Maybe you're a small-business owner who is short on time and needs numbers crunched quickly. It doesn't take long for the Excel expert to do the work. The spreadsheets will be ready to distribute when you need them, and nobody will know you didn't do the work yourself. Sometimes you need an extra arm to get things done, and using a confidential Excel expert can improve reports and presentations.
Or maybe you're preparing a presentation and need data to support your position. An Excel expert can confidentially crunch the numbers, giving you the information you need. You won't be put on the spot because you'll have the answers, and you can lay out your plan in an organized fashion.