Assuming you have passed this stage, the slot will continue to grant the user 15 special rounds and add the x3 multiplier to all the victories you have made. It seems that these waves can't be reactivated, so when you have a chance to do so, you'd better take advantage of them.
What makes this level more satisfying is that it can be activated during the Dragon Feature, which actually makes the title come true and doubles your destiny. We usually don't say that slot machines do just that. These are just two icons in the odds table, which means that when you play real cash, you have more things, such as searching for five crane cards.