MB, I mean that during limbing and bucking, it leads to poor positioning. For felling, less so.
When a person rests the side of the saw against their body, a lefty grip puts the bar and chain within about 2" of the leg. Loose chaps worsen the situation because they can be snagged more easily and pulled around, whereas with the righty grip keep the saw a full powerhead width away from your leg.
When limbing, and bucking from an upright position , I frequently rest the lower corner of the 3/4 wrap handle on my left kneecap, giving three points of contact/ tripod stability, allowing me to cut very close to the ground or other object with little risk of 'dirting' the saw.
A sawyer is hard pressed not to stand in line with the bar when holding onto the pistol grip lefty-style.
For a more experienced, well rested, and stronger sawyer, this last point is less important, but for less experience, fatigued, or less strong sawyers, it can lead to trouble.
Had that woman not had the her body in-line with the saw, the kickback would have missed her. She wasn't a weak rookie. A lot of people like to look down the bar when their cutting instead of using proper body positioning off to the side.