It turns out that Kobo are using the news feed just as I expected. The latest post, dated 23 July, has several prominent links to Kobo's website. this means that anyone using the app can navigate to kobo's ebookstore and buy ebooks with a minimum of hassle. it's not as convenient as the old ebookstore, but it is more convenient than any of Kobo's competition.
The interesting thing about this post is that it wasn't there when I wrote about how the new app had been changed. Kobo only added this post after the app was released. And they've left the post there for 10 days without a follow up post.
It is clearly intended to be a way around Apple's rule.I really hope that no one at Apple is going to be vindictive when this is noticed.