Even though the price of diesel is higher than gasoline, it’s STILL MORE ECONOMICAL. Do the math............
Better find out the price premium for the diesel hybrid first.
Diesels are an economical choice for passenger cars in Europe because the price of fuel is considerably higher there. However, you would need to drive an awful lot of miles for them to be economical here.
Hybrids aren't really economical here, though as their batteries get to have a longer life cycle and gasoline prices increase, they may become economical.
However, combining the higher price of a diesel motor and the higher price of a hybrid doesn't sound like an economical winner.
Gasoline motors also tend to be lower in efficiency at low RPMs, and the electric motor has good low end torque, so they compliment each other well. That's the reason I was told that we haven't seen diesel hybrids before now.
VW may have found a way to make an extremely efficient diesel hybrid, or they may have just found an expensive way of having the highest MPG in their class which will likely sell to some people despite it not being cost effective.