Doesn't have to be entirely slab sided, but going on the couple of people I know using pickups for work, they have added no end of toolboxes, winches, custom mounts, light bars and such so they can do their job miles from anywhere in the dead of night. The lovely clean stealth lines without a horizontal surface in sight of the Tesla seem entirely unfitted for being actually used for real work...

0-60 wouldn't care about drag much at all. Highway cruising would.