I guess it's a status thing, for folks who value appearing to have "status". I like having some status with an airline or hotel chain, that's about it.
Pickup trucks in general may be a status/lifestyle thing for many who never use the bed for anything serious. But anyone shelling out nearly $100 K for a truck probably isn't worried about fuel costs. It is kind of neat on paper than you can power your house with one of these things for a couple days with the right attachments.