This is nothing to do with einaregilsson as it is a _very cool_ easter egg, more just the comments on marketing.
Lots of people put lots of hard work into games people like. How many of them get a celebrity to play their game, let alone post on social media? There are plenty of games out there with thousands of users and 0 celebrities.
On top of that someone reached out to him and request they prank Mr Skywalker. Where is the initiative in that?
He was lucky to have a celeb play his game. He was lucky the celeb tweets about his game. He was lucky a friend of the celeb requested they prank him. He clearly capitalized on the opportunity and every nerd like myself loved this story because Star Wars + coding fun and now we are all checking out cardgames.io.
But to claim "this is how you do marketing" is a stretch for me.