It’s always good to draw, no matter how you go about doing it. Copying someone elses sketches (as an exercise obviously), for example, can teach you alot about how they created the drawing, how to properly shade, add reflections, etc. to make your stuff pop.
But I’ve also been taught throughout my life that to truly understand three dimensional objects, drawing still lifes or even simply analyzing form is the best way to go about it.
Regardless, the more you move that pen, the better you’re gonna get.