Ammo fragmentation offers a few distinct benefits. Most people who choose fracturing ammo do so for the additional killing power that it offers. Traditional ammunition will only cause a single, straight wound path. That is often enough to kill the target, but that is not always the case. When a bullet strikes a living target but fails to penetrate any major organs, the target will often survive long enough to escape. The wound might be fatal in the long term, especially if it hits a major blood vessel, but not immediately.
The fractured ammo creates several wound paths, which significantly increases the odds of hitting a vital organ. Even if it does not, it will still lead to additional bleeding. The greatly reduces the odds of the target getting away. It also ensures that the target will die fairly quickly, which is the goal of every true hunter.
The additional wound paths can even compensate for poor aim, which is a problem that plagues every shooter during periods of stress or excitement. They won't do anything for shooters that miss their target completely, but they can compensate for a shot that lands an a few inches away from the kill zone. Since the fragments radiate out from the ammunition's main path, it can compensate for pulling the shot in any direction. That makes them particularly useful for inexperienced hunters that are more likely to misplace their shot, but almost anyone can benefit from the addition security that these rounds offer.