And on top of that, Google's reputation of brutal power grabs on the web may make a difference in tone.
Importantly though, we shouldn't frame this as Apple vs Google. I can ensure you that both companies absolutely hate the open web and open computing in general.
If Google says it is to prove to advertisers that a human is seeing their ads, trust them at their word, with all the implication it entails.
There’s no stopping fraudulent behaviour, only defensive barriers to dissuade the non-nation-state actors.