Why should the Product Owner care that the Developers adhere to the Definition of Done?

A. To influence the Total Cost of Ownership of the product: Adhering to the Definition of Done ensures that the product meets the required quality standards, which can influence the Total Cost of Ownership1.

B. To have transparency into what has been done at the end of each Sprint: The Definition of Done provides a shared understanding of what work was completed and what standards were met as part of the Increment2. This creates transparency and allows the Product Owner to understand what has been accomplished at the end of each Sprint12.