They both (appear to) be surfactants (soap), without making an outrageous amount of bubbles. They are a benefit because they help reduce the boundary layer, the area of flow closest to the inner walls of a tube (or a waterblock), which in turn may improve cooling a bit.
The Jet-Dry is already liquid, so there is no worry about having solids running through a loop which could damage the pump. (although liquid dish detergent is also available).
Also, the soap should help prevent the growth of algae.
Hey, for $1.00, it was worth a shot. I just wanted something to keep my tubes clear.
