Download link is prominent(in top header) on krita.org ?? Do you mean you are not allowed to add link from Windows Store description. Which seems reasonable, i.e. equivalent of using Amazon to promote company site (alternate/competing store).
Would you feel similarly about AirBnB hosts leaving their contact information in the physical location so you could arrange bookings outside the platform? Just curious because I can see the value platforms provide in discovery and "bringing the customers to you" but once you have proved your worth to the customer, it's not clear to me why a platform-middleman is still needed.
It feels a bit like a dark pattern though if you consider a user that find it first through the store. I would like to know the percentage of users that consciously paid for it knowing they could also download it for free vs those users that paid for it because they didn't know better.