Short fights like adds that die quick definately dont need the full rotation and botd. I only use it on the add packs I know will let me have it up for the boss fights. I think dervys guide goes into the optimal rotations for quick adds. Fates don't need your full focus, but it is good practice, to lock in muscle memory.

You shoud definately be using it on bosses. Its not a big one for DRGs anyway, basically two smaller rotations with ogcds woven in.