That reason alone is why I would take CoH over anything else in dungeons. I may, huge may, take Apotheosis for some dungeons if I know that the trash isn't bad so I can have it for the oh shit bosses. That's the only reason I would take Apotheosis over CoH in dungeons, having a heal on the move is too good not to have in tight quarters.
Benediction will be horrible for dungeons, unless their is constant damage being taken by all members because you are losing Prayer stacks to the duration timer and not getting the full benefit of the talent. The same reasoning goes for raiding and Benediction.