My client wants to do an iPhone app because she's found that people are significantly more likely to use the iPhone app over a mobile optimized site. The iPhone app is very simple - it just displays a couple images and some text. As a programmer I'd much rather do a mobile site given the simple nature of the content. From a technical perspective I feel that it's overkill to use an iPhone app in this situation.
Does it make sense to build an iPhone app when a mobile site would suffice, simply because your users would much rather it be an iPhone app? Is there anyway to easily convince users that a mobile site is just as easy to use?