Why did Riven break her sword if she can repair it at her own will?

Seems like a major flaw in her story, not to mention all the jokes about her trying to balance how broken she is. Its going into my bank of most useless story arks. Next to the rebels blowing up the Death Star.

THE EMPIRE JUST MADE A BETTER ONE IN LESS THAN 10% OF THE TIME IT TOOK TO MAKE THE FIRST!

Not to mention the fact that in the new movies they have an even stronger weapon that can wipe out entire solar systems so... https://38.media.tumblr.com/tumblr_m2h6l7nQcJ1r3qup9o3_250.gif

Suck it New Republic.