This pane is mainly useful for healing/supporting classes and classes with special buffs/cures, but can provide very useful for others as well, including the raid-leader (keeping an overview).
Here you will configure which buffs are shown in the top-right corner of the player-frame. Only activate those that are of interest to you, or those you can cast and want to keep track of; i.e. as a rogue you don't bother if there is Arcane Intellect cast on the group, so why display it anyway?!
As a druid on the other hand you will want to know if Mark of the Wild is up, or if the priest just healed the tank with Renew, so that you don't need to waste mana and spam a healing-spell also...
Personally i like to know who has been soulstoned by a warlock, so i have this option activated as well.
This controls which debuffs are shown (the whole player-frame will be colored with this color-setting). Only activate those you can counter.
Notifications via system-message about the (de)buffs you can cure/recast. You also can set a key-binding for cure or rebuff, so when this message arrives you hit the key and the target will automatically be cured/rebuffed with the correct spell. Since the new version of CTRA and the newly introduced Debuff Curing System this feature has become even more powerful and works for "normal" parties now also (without notification, though). Byebye, Decursive...