Catalyzes the hydrolysis of dATP, dADP and dAMP into dA (PubMed:33926954). This step is essential for Z-genome synthesis (containing aminoadenine instead of adenine). Specifically removes dATP and its precursor dADP from the nucleotide pool of the host, preventing the incorporation of A into the phage genome and favoring the integration of the Z-base into the viral genome (PubMed:33926954). dATP + H2O = 2'-deoxyadenosine + H(+) + triphosphate dADP + H2O = 2'-deoxyadenosine + diphosphate dAMP + H2O = 2'-deoxyadenosine + phosphate Uses a typical 2 metal-ion mechanism to dephosphorylate dATP. Belongs to the Caudovirales dATP triphosphohydrolase family.