I personally find it weird and confusing when I see things like this. There are loads of closed source projects that use GitHub purely for issue tracking and feature requests and it just kind of feels against the ethos of it. Honestly for those projects I'm not really interested anyway if it is closed so after a quick browse in the org repos to see if I missed something, I just leave.
In your case it seems even stranger, if you wanted to have a landing page in GitHub but nothing else then why not have it as an GitHub Pages website rather than a repo?