The width of the collar has definite purpose---to spread the pressure of the collar over a wider area. Sighthounds often lunge at the sight of a squirrel or cat and can reach tremendous speeds even at the end of a 6' lead. The wide collar cushions the impact on the neck when it reaches the end of the lead.

An analogy can be made with high heels. Would you rather have your foot stepped on by a 100 lb. woman in spike heels or a 200 pound man in sneakers? The woman is putting all 100 lbs. into a 1/2 inch square area and the man's weight is spread over several square inches. She would have 400 lbs per square inch where he might have 20.