Mini games like poker, sharpshooter, race, knife throwing and supply drop (reaching a designated area within a limited frame of time) or wanted dead (killing a target with a specific kind of weapon), are a stepping stone in the main plot and allow you to earn more money. All activities in a given area require you to secure an outpost to unlock. Before you start doing supply drop, it is a good idea to secure all nearby outpost, in order not to run into an enemy patrol while performing the mission.
Although poker is the most profitable, it requires luck during card dealing. That is why, when there is a pressing need, I recommend that you do wanted dead which, apart from money will also give you experience points, as well as knife throwing, which requires releasing the button at the right moment. The most important thing, while loading the strength bar, is to make sure that you do not go beyond the green area. It is better to release the button before you reach the green area, instead of aiming at the middle of it.