Also he would have needed to implant the eye into something/someone (like he did with the crow) to activate it, wouldn’t he? The eyeball itself still needs a chakra source for the sharingan to be of use. (also I’m wondering now, bc I don’t actually remember if it was mentioned in shinden, but did Danzo know Itachi had Shisui’s other eye?? If he didn’t, Itachi probably couldn’t risk letting that info slip out by doing anything with it…)

[[ Yeah, he’d either need to implant it in himself or another creature. He’d risk too much. ]]