Standard zinc paint has limitations as a sacrificial anode. There's
less than one volt electrical potential between Zinc and stainless or
bronze. And the organic binder in paint makes great electrical
insulation; so only a small fraction of the paint's zinc pigment will
contact and/or interact with the base metal. Sacrificial anodes have to
be placed on paint-free metal surfaces for this very reason.
As to the wearability of zinc/aluminum paint...and I havn't tried the HD
product you describe. It looks good the day of application.
Regards, Boatdreams.