Flaws in your squat technique will hold you back from progressing. Overhead squats can improve the squatting pattern and should be a regular part of your strength training program.

The overhead squat requires a more upright posture than the back squat and you're forced to execute the squatting pattern precisely, otherwise the bar would drop to the front or back.

Have a look at the video. You can see the high concentration level of the athlete and accurate execution.

Related:  Do This 3-Squat Drop Set

Related:  3 Movements for Better Squats