So then why is WA only better based on hearsay?
Hearsay doesn't mean it isn't true. Simply means "information received from other people that one cannot adequately substantiate"
Everyone says that all Rabbis approve of it, yet I can't find a single one in Israel thats involved in the Kashrus scene to actually say that someone who doesn't eat regular Rabbanut can eat there. And that includes people who have had sit downs with the mashgiach and tours of the kitchen. Its largely stemmed from the bandwagon effect. So not to say that it isn't true, rather thats its unconfirmed with anyone in the know.
I hate arguing about the WA but you brought it up.