The U.S. Court of Appeals for the Ninth Circuit determination could have significant ramifications for all online operators who offer tokens/currency to participate in "free-to-play" or "play money" games -- whether that be poker, casino or otherwise.
Case stems from 2015 Kater vs. Chruchill Downs (Seattle, Washington).
It is not the view of the Washington Gambling Commission that play money poker constitutes illegal gambling, and no enforcement action was even hinted at. Pokerstars, on their own accord, stopped offering the games. They gain nothing by offering play chips in Washington, so it's no loss for them to drop the games.
A case of 'better safe than sorry'
But this civil case did not suddenly make play chip poker games illegal in Washington