Purchasing from an iOs App

[paolo mazza]

Referring to  verse 11.13  of the holy "App Store Review Guidellines"
(last edition) ,  "Apps that link to external mechanisms for purchases
or subscriptions to be used in the app, such as a “buy" button that
goes to a web site to purchase a digital book, will be rejected"

What about a "buy" button that goes to web site to purchase wine or cars  ?

I mean, restrictions apply only to materials to be used in the app or
to any kind of product?

All the best

Paolo