Kettlebells are usually used for explosive movements or cardio workouts. They are rarely used for strength or hypertrophy training. So it depends on what your goals are. Kettlebell workouts can help you to define your chest by burning calories, and beginners will definitely see an improvement in their chest strength and shape. But more experienced lifters may struggle to see progress, even if they use a heavier weight, as kettlebells are not ideal for hypertrophy. Sticking to conventional chest barbell and dumbbell exercises may make more sense for experienced lifters.