Drawings are not all the same, nor are the benefits. We're going to briefly explore the 3 basic drawing types and what they do.
Doodles are a simplistic drawing that you do while you are engaged in something else. It takes minimum effort or concentration, in fact somethings its your subconscious moving your pencils. Even though you aren't really creating anything significant with this type of drawing, your body is learning basic strokes and pencil/pen movements.
Sketching is usually done with a purpose. You have in mind a particular subject and attempt your best in creating a sketch. This is the most common approach to practice in many intermediate artists.
The last is the study. Its when you vet a particular subject
or artist and practice several sketches dedicated towards that same subject in order to improve or better understand the subject. Hands, faces, even other artist's styles all become subjects to study. This is very common among advanced to professional artists.
Now you have something to think about before you put the pencil against and create a new drawing.