We can have a complex disposition e.g. being honest with friends and deceitful towards enemies. Being poker-faced is cultivatable. The part that virtues play in the good life depend on such dispositions - persistent and not too finely discriminating. Conventionally, courage is associated with strength. We imagine that the brave will more likely achieve their goal unlike the foolhardy who may undermine their plans or timorous who is easily turned aside.
Most worthwhile enterprises involve risks.
The courageous can enjoy the activity and risks. The coward cannot. Vice and virtue here become apparent to others. Yet in egotistically cultivating a virtue this is a rational line of choice. Sometimes those who behave rashly are lucky and are rewarded.