They're built inside the bed, but they don't preserve any space. They are fatter than normal bed walls. I just don't like auto manufacturers making decisions for me, especially when it comes to space things.
If I want extra toolbox space, I'll buy a Honda Ridgeline. If I want a truck, I'll buy a truck. If I want a toolbox, I'll buy a toolbox. If I want a utility bed, I'll buy a utility bed.
... but to pay for a truck that already has something in it that I may or may not want? Not for me. Its a way for them to charge a premium price for a substandard addition. Its no different than standard A/C or standard chrome. Just because its "standard" doesn't mean you're not paying for it.
If I want a truck, I buy a truck. If I truly need toolbox storage, I don't want cheap, flimsy plastic boxes in the fenders. Those boxes are there to sell trucks to regular people who want the "ruggedness" of having a truck with toolboxes. Some suburban yuppie will buy that truck because it has the cool toolboxes like the contractor trucks they see, not because they need tool boxes.
Its like when they used to put CB radios in cars in the 70s. They were junk CBs that wouldn't transmit past your bumper. If I want a car with a CB, I'll buy the car I want and ADD a radio. Don't try to soak me for extra money with a "standard" CB that is a piece of junk.