From go/autofill-validation-dilemma:
"Use the validity states only for scoring and then ordering the profiles while showing suggestions. Using the validity for scoring the profiles, would mean that we care for the validity in the profile level and not field by field (we don’t care which field is valid, which is not, we care if the profile is valid as a whole, meaning that all the fields should be valid). This way, for suggestion, frecency would change to frescocency!"