Product, design, and engineering may have the perception of overlapping roles. In reality, each function has highly distinct responsibilities.
Design: Design the optimal visual and user experience for the product.
Engineering: Build the product. Suggest how the technical road map can drive product and vice versa.
Product: Set the product vision and road map and ensure the company builds a product that the user needs. Make trade-offs and prioritize between design, engineering, and business concerns.
While design is often focused on the optimal design for a product, and engineering on the technical side, product’s role is to make trade-offs and prioritize based on inputs from design, engineering, legal, customer support, and sales/marketing/customers versus the broader business needs, competitive environment, and company strategy.
Ambiguity arises largely due to designers thinking, “I own the design, why is product telling me what to tweak?”, engineers thinking, “I own the technical aspects of the product, why is product asking me to stop working on feature X?”, and product sometimes stepping on either function’s toes.
In reality, product management should be viewed as the function in the middle that needs to make holistic trade-offs on all aspects of the product and represents the voice of the user (while making the proper business trade-offs). This role obviously requires a lot of trust from design and engineering, which is why a bad product manager can ruin perception of the role in an organization.