Any projectile can potentially benefit from using wool wads. Some folks do report improved accuracy when using them with patched round balls too, especially along with heavier powder charges.
The only way to really determine how much they will help is too experiment.
Every rifle and projectile is different, but generally using wads won't hurt. They may increase velocity just a little bit, but using them is supposed to help increase overall consistency.
Most people don't use them very often because they increase the cost per shot and aren't always necessary or produce a noticiable benefit. So folks mainly use them when accuracy and performance is lacking and some improvement would be beneficial enough to make them worth trying out.