That's why I put it on mobile only in the first place.I don't use NSC on mobile, so... mobile!
Despite only ever using NSC on desktop, it seems sensible to me that any permenant ad would be less intrusive on the bigger screen of a desk/laptop than on the smaller mobile screens.
On a portrait-oriented phone, it felt like the sticky bottom banner was largely tucked away, as it feels as though naturally my eyes are towards the top of the screen.