What makes you different from the others? – This is probably the most important question, since many PPC agencies are competing for your business, why are they different? Expect a bit of a "marketing" flow in this answer, but see between the lines, agencies need to be passionate, dedicated to their clients and offer something unique.
Describe our business and how it looks in the market – PPC agents in Wolverhampton need to know the client's business and products, they need to be a continuation of the marketing team so they need to know your business. It also shows if the agency did the research and took the time to understand your needs.
If a business, even a large one, was to hire this person, they may find that these potential improvements in profits are mitigated by the high cost of the staff member.
This only really works when hiring a PPC agency, because they benefit from economies of scale by having their highly trained search specialists work on several clients at a time. While they may not spend all their time on your account, they do generate incredible results – and that is what you are paying for at the end of the day.