Put him in there mostly to make the 'Guptill isn't a bad option on this tour' point.You'd pick Guptill ahead of Latham? Why?
If I were trying to justify it, I'd be arguing that with Fulton gone, NZ lack a high-quality slipper to the spinners. Guptill can be that man; he's nuts in the field. Plus if Latham is looked at as the long-term opener, it might not be the worst idea to give him experience in that position at home first, although in fairness being up against Roach and Taylor on these decks would probably be an easier initiation to Test opening batsmanship than starting out on an underprepared Queenstown greentop.