I think it depends on the type of application. If the application is targeted at photographers, I assume that the developer has to be pretty proficient with photography.
If the application is targeted at construction project managers, I don’t think the developer needs to be an expert on photography. Though, I imagine they need to understand things like lighting.
At the bottom of this article, I wrote a short analysis of business and development trends for 360 applications. For applications like sales presentation or corporate training, I imagine that the photography skill level needed is about medium.
For an HDR application like Ichi is building, I imagine that more photography skill is needed.