Design serves two primary roles--functional and emotional.
The separation between these two roles used to be distinct. Engineers dealt with the product's functional design, primarily the backend aspects. Product designers focused on crafting the desired emotional outcome associated with the product's attractiveness features, the customer facing aspects.
Technological advances have narrowed the gaps between the functional and the emotional to the point that they complement each other, and to the degree that they are sometimes difficult to differentiate. As long as the distinction between the roles of engineers and designers was maintained, there were negative implications on the product's user experience.