It's true that "bluffing has minimal value against best play", but no human is in that situation. Even super-GMs will play "bluffs" if they are behind (or playing a lower-rated player and sure they can recover later. or just for fun if the stakes are low).
And that's not even mentioning optimal strategy under time pressure. For instance some of the Lichess tournaments are structured such that winning fast is more valuable than winning slowly because the resulting score comes from how many wins you can get in (or in other cases, how big of a streak you can get). So people will play in a way that optimizes for winning quickly by taking big bets / bluffing / creating chaos with un-calculated gambits, especially if they have a good reason to believe they're better than their opponents.
It wasn't the most accurate game of the tournament, but the most instructive as far as the psychology of chess goes