One Hand on the Ball
The round top spreads pressure across your palm instead of concentrating it on a bar, so you can lean body weight onto a small digger without the end of the shaft biting into your hand. That makes the ball handle a natural fit for shorter tools driven from a kneeling position, where the push comes straight down from the shoulder. It is not a two-handed shape and does not try to be; the point is comfortable force through one hand, hole after hole.
Kneeling Recovery Is the Job
Picture the standard park recovery: detector set down, knees on a pad, one hand running a pinpointer, the other cutting around the target. A ball-top digger keeps that second hand comfortable through a hundred repetitions of push, saw, and lever. On manicured lawns, where the plug has to be small and neat, the control of a palm grip matters more than raw leverage.
If You Need More Handle
The moment holes get deep or the ground turns to clay and roots, step up the leverage: a T-handle for two-hand twist and boot drive, a D-handle for a closed gloved grip, or a standard straight handle for the do-everything middle. All of it lives in all shovels, diggers and picks.