I can’t speak for the developers, but I think it is safe to say that there is a whole lot more functionality on the website (= desktop app) than could ever be packed into the mobile app and have it remain remotely usable as such. So it is streamlined to the most needed functions, which tend to center around capturing and posting observations real-time, and basic searches and interactions with other observations on the site. But it never hurts to ask for something new!
That said, I’ll just mention for general information that the Forum is currently not accepting new feature requests specific to the iPhone app IF the feature is already available on the Android app, as updates to the iPhone app are already a priority: