Respond to the given:
I think that product functionality is the one I would choose first.
1. Product functionality - I need transportation to get from one location to the next. Primary function is met which is transportation.
2. Product design - I need a specific type of transportation to get from point one location to the next based on design. Product design will be the focus because the function of a product will determine specifics.
The two have a tendency to work very close with one another because of the use of the product whether it be for normal driving on the highway in dry weather or for snowy/muddy conditions. The features to accommodate are very important. Driving in bad weather condition may require you to have a vehicle with four wheel drive to travel.
In summary, product functionality is determined and satisfied first. Then the product design is streamlined based on the function and how the item is used.