Overall, there are many ways in which a business may gain:
Potentially, an outcome of this could support effective marketing/public relations, for example, in terms of a business celebrating X years since starting trading. The interview(s) could then used as a means of publicising its corporate identity.
Alternatively, the business could be venturing into a new field and was seeking to demonstrate how its past was relevant to the modern-day setting.
From another perspective, knowledge gained via the interview(s) could contribute to a company archive, preserving its history, supporting the continuity of business, for example, when people in the business retire (or are made redundant) and they take with them skills, expertise and knowledge of the company and it's products/services and of course it's working history. The audio could then be applied in the training of remaining staff.