Sorry not sorry for my smugness
I think the main problem most people have with Z-Moves is that they feel like a “Press here to win” button, whereas we’ve seen enough times a ME or Dynamaxed Pokémon was defeated.Watching this match again it's obvious some people's bias against Z-moves clouds their judgement. Pikachu couldn't keep up with Metagross' speed and the Z-move was used to hit it out of the air. The good thing is Metagross didn't just stand there and take it, it dodged 3 of the beams and deflected one of them, so only 3 beams hit it and knocked it out of the sky. Then before it could recover Pikachu got an Iron Tail.
Also remember this increases with a critical hit and Dracovish's strong jaw damage earlier in the match. Taking 3 strong attacks should be enough to bring it down. Z-moves are no less valid than either Gmax or Mega evolution
Though, I think this criticism should be directed towards Game Freak and not the anime, because they work like this 9/10 times in the games, too.