It comes down to quality and consistency.
An individual marketing executive will not have the full set of skills to develop campaign content. For example, a skilled writer will not have the ability to design – and both skills are essential. Videography is also a very specific skill set. Engaging an agency (like Catalyst Content) will enable an SME to create quality content across the board.
SMEs often get their in-house talent to execute marketing on an ad-hoc basis. They often run out of steam and prioritise other work before marketing.