Well, for one it makes Luke’s intentions regarding his plan be about two different things (distraction and accepting his place as a legend). And for another it removes the implication that some downtrodden kid managed to hear the story as it trickled all the way down from people who are supposed to be serving the First Order, not spreading propaganda against it, which has always kinda bothered me.

EDIT: Just had an amusing thought. I suppose this is why Hux had to be made a spy in TROS, because how else would the story have gotten out? lol