Using a swim snorkel means you are not always breathing to your dominant side which helps make your stroke is more balanced. This is key for sprinters who need a smooth, kayak-like stroke turnover. Being able to turn your arms over quickly and evenly gives you a smooth stroke that maintains velocity. For mid-distance and distance swimmers the benefits are in balancing out the workload across both sides of your body to avoid over-loading one side which can lead to injury and strain like swimmer's shoulder.
By eliminating the need to turn the head for a breath, the swimmer can focus on technique and body position for efficient swimming. In many sports, the participant is encouraged to practice a specific motion slowly. The snorkel allows you to practice technique slowly in swimming.
