that'd be a death sentence, Kakashi without help gets drained from normal use with his sharingan, which is why he keeps it covered. if he got both of Obito's eyes there's no way he could prevent the double drain of his non uchiha body constantly using a sharingan.
True, thus meaning a sacrifice must occur.
I agree it's like an ultimatum for Kakashi, yet his mentality makes this event a posibility.
If Kakashi believes that his actions even if it means killing himself will save Naruto or the Alliance he will do it.
Background story: Rin is dead, Obito soon follows, Minato dead. His year is almost gone. Also he would be the only decent sacrifice atm. Plus kishi should show us what the true power of Obito's sharingans is.