Corrosion protection issues for tank foundations

I remember that the anti-corrosion treatment on the back side of the tank bottom plate was removed per the specifications

How to understand the removal of the requirement for anti-corrosion treatment on the back side of the tank bottom plate?

Cathodic protection for the foundation slabs of domestic projects is relatively uncommon; however, some specialized teams working on storage tank foundations require such protection (to protect the tank bottom, not the rebar). In foreign projects, where there is seawater corrosion, cathodic protection for the foundations is sometimes applied (or epoxy-coated rebar is used, but the two methods cannot be used simultaneously). In China, corrosion prevention for foundations is usually achieved through the use of admixtures, impermeable concrete, and the application of epoxy asphalt on the surface to prevent corrosion caused by groundwater. To prevent corrosion due to fluid leakage, anti-corrosion coatings are typically applied to the inner surface of the foundations, crystalline waterproofing agents are used, and PE membranes are laid as protective measures.

Is cathodic protection for such footings rarely used? Personally, I think this is not possible, as no groundwater will reach the bottom of the tank through capillary action. What do you think? Additionally, is this type of structure at sea mainly used to protect the foundation itself, the rebar?