This is smart. On location play is too quick on a fast machine for some of my friends. If they knew they would get at least “x”amount of time to play I think they would play more.
It could also be a way to increase play cost without losing novice players. If game play cost raises to $1.50 a play or 3 plays for $3 on newer machines many new players might only play once. Yet with a healthy ball save dynamic, they might feel like they are getting more out of their money and keep dropping more coins.