When I joined the Creator Program on Saturday (4/22) it asked for my requested Creator Code which was granted. The documentation said “Your Creator Code is used by your followers to show their support.” I assumed this was the name your islands would be published under, it is not, it is your Fortnite name. Why is that?
Good point, you don’t want your in-game name to be the same as your creator id.
Neither do I, because playing ones own maps you dont want other players reaction be like “oh he knows all the secrets of the map, that’s totally unfair!”
I don’t know how it works, or why it is like this, but maybe it has to do with teams.
Like if several people are working under one creator code the individuals can still get credit for their maps, or something like that.
Just a guess, hope we will get an answer soon 
edit: Congratulations!!!
It gets even more confusing. The creator code is used off site on websites that have API hooks into fortnite. Those sites have my creator code, not my user name. It’s hard to brand yourself if Fortnite/Epic is not following its own rules. Use the Creator Code when publishing a map, not my user name.