I think this comes down to ambiguity over what "optimal play" means.
There's a poker strategy we might call 'deterministically' optimal play, which consists of precisely assessing each hand's expected value with little to no bluffing. This is already common in online cash games with both bots and players running multiple games at once. And you're right - it's excellent at running net-positive and not losing, but unlikely to win significant tournaments.
Pluribus, though, is playing something close to game-theoretically optimal poker. In playing against itself, it's attempting to develop a takes-all-comers strategy with no exploitable weaknesses. That includes bluffing and calling bluffs - the goal is simply to find a mixed-strategy equilibrium where those moves are made some percentage of the time, in proportion to their expected payoffs. This can involve doing all of the same basic operations as pro players, like valuing button raises differently than donks or attempting to bluff based on how many players remain in the hand. The distinctive limitation is simply that Pluribus plays 'locally' optimal poker with no conception of opponent's identities or behavior in prior hands.
that's a helpful explanation thank you! I was misunderstanding the statement about Pluribus not modeling its opponents between hands as between rounds - it's definitely modeling its opponents and detecting bluffs by understanding when a bluff is likely strategically based on each opponents actions so far in the hand, it's just not taking anything it learned into the next hand.
I could see this being an effective strategy in a WSOP, that ability to perfectly forget the previous hand is probably more valuable than anything the way WSOP champions play. I could see it coming down to whether or not the ability to exploit a reliable tell during a pivotal hand matters more than 10% of the time.
There's a poker strategy we might call 'deterministically' optimal play, which consists of precisely assessing each hand's expected value with little to no bluffing. This is already common in online cash games with both bots and players running multiple games at once. And you're right - it's excellent at running net-positive and not losing, but unlikely to win significant tournaments.
Pluribus, though, is playing something close to game-theoretically optimal poker. In playing against itself, it's attempting to develop a takes-all-comers strategy with no exploitable weaknesses. That includes bluffing and calling bluffs - the goal is simply to find a mixed-strategy equilibrium where those moves are made some percentage of the time, in proportion to their expected payoffs. This can involve doing all of the same basic operations as pro players, like valuing button raises differently than donks or attempting to bluff based on how many players remain in the hand. The distinctive limitation is simply that Pluribus plays 'locally' optimal poker with no conception of opponent's identities or behavior in prior hands.