Those are very small targets. They’d be hard enough to hit on a static range with no pressure. They’d be even harder to hit when moving, in a stressful situation, at close range. If you miss, you could hit someone else. Even if you hit them, the bullet will probably go right through and into whatever is beyond. This is why you aim for center of mass. Easier to hit, less chance of overpenetration, and more effective in stopping an attacker in a life-or-death situation.

Despite what the movies may show, you can’t just shoot to wound. If you shoot someone in the leg, and hit the femoral artery, they can bleed to death in seconds: https://pubmed.ncbi.nlm.nih.gov/17334183/