Normal Yahtzee
For example, in King of Tokyo, anyone outside of Tokyo can only affect whoever is in Tokyo, unless they have powerups that state otherwise. So, when you are outside of Tokyo, you don't really need to be engaged with the other players also outside Tokyo, because they can't affect you.
Reverse Yahtzee
Instead of rolling dice and using them to create sets for yourself, you roll the dice and distribute them to other players.
The player who is rolling the dice during their turn is engaged, because they need to decide to whom they want to give certain dice and to whom they do not want to give certain dice.
The players who aren't rolling the dice are also interested, because they can only score points by creating sets with other players' dice.