I have used atone in battle before (specifically in lower guk) - it is not
time efficient, but it is rather amusing to see the mob change targets
immediately after forgetting it hates you. Works best if it is still pissed
at the rest of your group members.

Another fun trick with atone is if you happen to fight a froglok shaman or
other pet casting mob. Once the master is dead, if everyone in the group is
ignoring the pet (ie - not attacking) You can atone the pet and it will
suicide (usually).

The only time I play with atone is when my group is not getting beat up
hard. More to "play" not to be more effective in combat. :)

~Sirensa
Solusek Ro