Can’t reforge, can imbue but only if property weights allow. Only practical use I know of is if u got some w/ very low eaters (eater weights r imbue point sponges) u could imbue a complimentary property. The given high property weights could offset a specific jewl weight (ie. damage increase) but effectively locks the character & suit into using only that kind of weapon which would have extremely limited gameplay.
I liked the idea of them when 1st seen but practical use badly missed the mark. They’re largest practical use is being a curiosity or unravel mats.
If they were given some hidden extra damage mod like an older invasion weapon once was, then I could see a slim possible use but as is they’re a waste. I have seen no such hidden damage mod in limited testing. I could b wrong tho.