On my first day of training at Haribhakti & Co, the Partner overseeing me, while discussing the value of the CA curriculum, mentioned an interesting aspect. He said that even the junior most articled trainee is treated with respect and caution by the senior client staff. Requests are complied with promptly. This point was NOT made for recommending power politics but to emphasize that when all the company records are open to a CA firm, there is very little to hide after that. Even consultants need to seek data specifically from client and generally do not get an open ID access like the CA firm does.
A trained person can diagnose issues with the 'professional view' and then use it to cross sell services across the board. A CA knows both sides-how data is gathered/audited..and how it is used. That makes it easier to know what to ask and whom to ask. In information intensive professions like internal auditing, management accounting and even operations consulting, such an edge can often prove vital