Banksy's Pest Control art authentication service

Strange - trying to legitimize provenance for an artform that explicitly defies provenance by being randomly and secretly distributed in public places.

Seems, I don't know, contrived? insincere? convoluted?

What does it say on a certificate? "This secretly created art by a secret person and given away with no paper trail, is the real thing by the real guy"? What does that even mean?