I believe the animation has nothing to do with payout, it is just an animation to show that you rolled 7s no matter where rolled it.
Great to hear that you win something from the game, you should try it with real coins IMO.
Who knows that you can hit 5/6/7 7s to win something from the prizepool?
Play with small amount is enough to test your luck as what I did, but I have no luck in this game.
Fruitsler slot is my favorite so far, although there is no free spins feature but sometimes I hit nice payout.