Should be a base running setting for hitters, same as base stealing. I build lots of speed teams and try to get all 17's on the basebath except for catchers and set my team for VERY AGGRESSIVE base running.
Typically, get about an 80%+ success rate which makes it very worthwhile.
This team as an example took 246 extra bases over the course of the season and was only thrown out 43 times:
https://365.strat-o-matic.com/team/misc/1697803Compare that to this team that only took 90 extra bases all season:
https://365.strat-o-matic.com/team/misc/1625284That's literally an extra base a game taken and only 25 more thrown out. It's all about the speed.
If you wanna take extra bases, get 17's on the basepaths and you'll be fine.