I'm asking about if we should use IAP or not into our app, below is our business model,
We provide users with discounts and offers from merchants across different categories. We provide some offers for free but offers from certain tiers of merchants are only available for users who pay for them because we have to give these merchants some incentives to work with us such as ad campaigns or subsidies. We need to know the best way to get these payments from our users.
It is unclear whether App Review will object but if the app unlocks code within the app and therefore displays or does something only after the user makes the payment then you have to use IAP. You might try to separate the 'display-for-discount' into two streams. One is the 'display' capability that you could sell for a small charge and use IAP and the other is the 'discount' that the user would separately purchase using a third party payment system (or Apple Pay).