Worthless now

That's just your opinion. Mega man has proven that bungie has control of Xur. Considering they can change xur 's load out anytime, what's to stop them from making it happen?

Bungie can also control Xur so one way or another, as long as he sold it before, he can and will sell it again. People thought he would never sell the Ice Breakers again and he ended up selling it 3-4 more times. Its a matter of time before he sells Gjallarhorn.