Nicki only decided to release Super Bass as a single because of how popular it got once Taylor Swift covered it. It wasn't part of her planned singles, that's probably why it was left off of the main album
Isn't Ellie's album called Lights? How was Lights a deluxe track? Lol. Idk about the UK but isn't it the first track on the US release?
It's the first track on the US edition of Lights.
Lights was originally released in the UK without it, but then released with 7 more songs about a year later (Similar to Ke$ha's Animal/Cannibal) as Bright Lights. Bright Lights added 6 songs to the original album, and Lights is the first song of those 7.