Only for in app purchases of Robux. They are uniquely allowed to distribute their own app store (not based on HTML/JS applets) within the App Store, which is ag

Only for in app purchases of Robux. They are uniquely allowed to distribute their own app store (not based on HTML/JS applets) within the App Store, which is against the terms that every other Apple developer agrees to. And they are allowed to use a virtual currency that can be obtained elsewhere without an Apple Tax to pay for digital goods purchases inside an iOS app, bypassing the IAP system, again against the terms.