How does this translate to software? Well, even the biggest smartphones can feel pretty tiny when you have relatively large hands. Trying to play, for example, a time-limited match-three game that depends on both accurately seeing the board and being able to make precise movements can be an exercise in frustration when the fingertip used for the movement can cover more than one of the elements of the gameboard. Since it's a game, it's mildly inconvenient, but there will be other places where the frustration levels will be greater.
After all, little things, repeated often enough, can still add up to big aggravations.