The phrase "extra incentive" means an additional reason or reward that motivates or encourages someone to do something. It is a bonus or extra benefit that helps to increase someone's willingness or desire to take action. Full definition
Fans of the series will be given extra incentive to buy the game again on Switch. (cultureofgaming.com)
There doesn't have to be a tournament at such an event, but tournaments can provide extra incentive for competitive players to take interest. (ozhadou.net)
For kids who need a little extra incentive, consider a reward system of some kind. (verywellfamily.com)