I don't even understand why this is a thing. What possible benefit could there be for linking in-game activities and real world identity?
What benefit is there to doing anything? It's down to the person. Playing SWTOR is a real world activity. I am actually playing this video game, working at advancing through it, why not share achievements with other people who are doing the same? It's not unlike runners who post their run times through apps, or people who post any of those mini-game updates, or someone who mentions that they just watched a movie, or links a book.... all activities quite separate from Facebook that are shared on the site.
It's just a choice. If you can't think outside your box and speculate why someone else might want to do this, then I pity you your limited imagination.