I think folks wear kilts for their own unique reason, but they have to be worn according to what works in that group.
I think that kilts would work in the goth culture, or at least seems to from my viewpoint which is admittedly as an outsider. But I can see where a black kilt would fit in just fine,
There is room for non-traditional kilts in lots of circumstances.
I have a black kilt, but it's made of canvas and cut with a full apron and I wear it as a dress kilt usually with a grey harris tweed. A black leather kilt would not be my style nor give me the same look.
Goths I would assume would love a black leather kilt, but my canvas, full apron one probably wouldn't make it.
Hey...wear what works. Kilts work in just about any group depending on the occasion and how they are worn.