Using any of these spells, (my warden, fury and ranger all have them), moves you lower down on the mob's hate list.
If we're talking about a solo fight, lower on that list doesn't really help you since you are the only one on his list.
These spells are really designed for reducing aggro in a group fight. My warden has used them while in a duo and the mob always spins right back around and concentrates on the tank like he should!