I've always thought they were worth it. I've occasionally had other players give me JC master writs that they didn't consider to be "worth it," and I've either done them or banked them for the future. Now that the tempering materials are easier to get and our old existing stock was basically multiplied by 10, the biggest thing holding me back from doing all of my banked writs are the rarer trait materials.

I've been doing all golds but only the purples in the normal traits. Not worth spending up to 20k for the trait for 30 vouchers, same as when they were blue