First, it's very confusing that neither the name, nor the description, nor the icon of the item changes after you've used the Golden Grail on it.
But more importantly:
Why does it turn robes into some horrible, muddy, mustardy yellow color?
Gold thread exists, you know! I've seen some amazing fully golden robes that one of the emperors of China wore.
I hope this item will get some TLC in a patch...