Wider stance squats allow people, like myself, who do not have ideal proportions for squatting, to have an easier go of the lift. Most every time I see a newbie having trouble with the squat, I recommend trying a bit wider stance, usually they thank me because the advice helped. At 54, with arthritis in both knees, a wide stance makes it possible for me to continue to squat. Same with deads, a wider stance takes lots of stress off my lower back and lets me lift heavy with no problems.