They are like a super versatile assistance exercise. Sometimes people go lower, under the knees, pushing the hips way back. This hits your hamstrings, and can help you learn to break weights off the floor.
Or you can just go down right below your knees, and pause down there push your chest up and pull your lats down, to learn to stay tight. And to pull the bar into yourself or scrape up your legs when you do regular deads.
If you stay more upright, and only go down to the top of your knees, you can target your glutes more. This can help with your lockout.
Since its not a competition lift, use it to get what you need.
You can add bands anchored to the floor to stress the top. You can attach the band to both ends of the barbell, then stand on it to really work your hamstrings. You can use the band to pull the bar away from you, and focus on pulling back.
Maybe you could even elevate your toes, to shift your weight to your heels, but I never tried that.