From what I have been able to gather, any purchases within an app that are either digital goods or delivered digitally are considered IAP's and thus subject to Apple's 30% commission. However, any purchases within the Fiverr app are not considered as IAP's, even though the majority of the services you can purchase are of digital goods and/or are delivered digitally.
What is it about their product that makes them different from any other digital content that is subject to the app store commission? Is it that they are unique, one-offs that are made to order? That there is back-and-forth correspondence between buyer and seller? That they are services rendered by an individual, even though the end product is almost always digital media?
Any help or clarification on this would be very much appreciated, thanks!