What exactly is apple looking for when they ask for an in-app purchase screenshot?
Do they want the purchased content in action or the store interface? what if i have a bunch of products that are very similar can I just use a single screenshot for all of them?
On Page 85 of the iTunes Connect Developer Guide, it states:
The screenshot should be a clear picture of your in app purchase in action...
This means it has to be some representation of what the user actually gets for the purchase, not how it appears in your store GUI.
This is just a hunch, but from having discussed this on other digital distribution products, it's important what claims and warrants are made during the checkout process, so that when credit card companies issue chargeback disputes, there is a clear record of how an item was portrayed to the user.
I don't know if this is what motivates Apple in this requirement though.
Apple say the pic wont turn up in the itunes store. I'd say its to help them confirm its working in the app review process. I know they look at in app purchases carefully, a lot of people screw it up, so its probably so the reviewer can confirm it actually unlocks something