tobi's eyes also not his.kakashi might not have developed it so far for chakra conservation reasons.Kakashi is not an uchiha and his sharingan is not he's those to reasons is why he can not use obito's eye to it's full capabilities
thats because tobi is always using zetsu to spy on peoples battlesI think kakashi just didnt learn how to use it all the way yet.
tobi has the rinnegan and can use it as well