The above seems correct.
The reason is probably simple: in text documents like scripts, storyboards and other office materials, you can spell it as one long word the way it was meant (stardestroyer) but when designing text layout for maketing it is better to break it into two smaller segments. Stardestroyer wouldn't fit on that toy box with the layout they have there.
Random, unsearched theory of mine that I just made up right now. :p