Golden Darkness is pretty weak even having such an overpowered skill, the dress is not suitable for combat and lacks training.
Still is one of the most loved characters of the show, anime is full of faggotry but the manga is quite decent, if you havent seen the anime dotn do it, read the manga instead.
The writers just don't let her use her powers to their full potential because Eve was overpowered in Black Cat. Case in point: a few times during the series, Eve created objects not attached to herself by shedding nanomachines and forming them into things like a replica of Hades.
Given that Eve and Yami are essentially the same person but Yami has no qualms with killing, there's theoretically nothing stopping her from shifting her hair into a battery of miniguns and conjuring an infinite supply of bullets.