Do we really need a Product Owner—we have someone in the Organization who does their regular, full-time functional role as well as the duties of being a Product Owner.
The Product Owner needs to be a full-time role within the Org. Once the Product Owner is freed up from their functional duties, they can then focus on working with the Team more frequently.
The Product Owner serves as the liaison between the Team and the Stakeholders. To the Team, the Product Owner is the voice of the Stakeholders, representing their needs, wants, and desires for the Product.
According to the 2020 Scrum Guide:
The Product Owner is accountable for maximizing the value of the product resulting from the work of the Scrum Team. How this is done may vary widely across organizations, Scrum Teams, and individuals.
The Product Owner is also accountable for effective Product Backlog management, which includes:
Developing and explicitly communicating the Product Goal;
Creating and clearly communicating Product Backlog items;
Ordering Product Backlog items; and,
Ensuring that the Product Backlog is transparent, visible and understood.
The Product Owner may do the above work or may delegate the responsibility to others. Regardless, the Product Owner remains accountable.
For Product Owners to succeed, the entire Organization must respect their decisions. These decisions are visible in the content and ordering of the Product Backlog, and through the inspectable Increment at the Sprint Review.
The Product Owner is one person, not a committee. The Product Owner may represent the needs of many Stakeholders in the Product Backlog. Those wanting to change the Product Backlog can do so by trying to convince the Product Owner.
Regarding Scrum Events, the Product Owner:
Only the Product Owner has the authority to cancel the Sprint if the Sprint Goal becomes obsolete.
The Product Owner ensures that attendees are prepared to discuss the most important Product Backlog items and how they map to the Product Goal. The Scrum Team may also invite other people to attend Sprint Planning to provide advice.
Now, does any of the above sound like an add-on task to a different full-time job? Not a chance!