BKB: It does use Moose's syntax and infrastructure for object inheritance (see the "extends" ?).
D::V::C::Email and friends do not exist in a vacuum. The value of a validation system does not necessarily derive from its implementation of validators but from the unified interface it provides. To me, the fact that ::Email uses a five-star validator in three lines of code is far superior to yet another potentially-faulty implementation in any number of lines.