Pushing requires a very specific form to be efficient, rigidity of the whole body, straight posture, locked arms, etc, while pulling leaves this effort to the object/thing you're trying to move.
Just think about it - if you're pushing a large object with your arms, if your arms are not straight and locked at your elbows/shoulders, the weakest point in your force is at your biceps, which are a fairly weak muscle compared to, say, your glutes pushing from the ground. However, if youre pulling it with, say, a rope, the rope is the thing thats straight and taught, while youre free to apply force as you wish. This usually involves back and leg muscles exclusively, which are amongst the strongest in the body.
There's also the fact that pulling also sometimes allows you to apply the force closer to the body's center of mass, which makes it much more efficient that elsewhere
