installing pond lining clay

What is a pond lining clay?

Sodium Bentonite (AKA the best pond lining material) is a milled mineral (almost dust) that works as a barrier between the pond soil and the water.

If you spread the bentonite over the dry pond and mix it with soil and water, you will get a low permeability mud that will seal the pond base.

So, if the pond lining clay does the same as the plastic liners, why should I install it on my pond instead of an RPE liner?