Observational skills are an essential aspect but not the most paramount by far. The master draughtsman never draws what they see, they draw what they know to look for. The master draughtsman doesn’t shade to turn form, they SHAPE it with planes to create form. They don’t copy nature they interpret it. Their skill-sets are intuitive, and their brains remain fully engaged. Drawing is visual thinking it is an intellectural business. Drawing for observation without using your mind’s eye is craft.
They develop a knowledge vault of inFORMation and an intimate sensual relationship with their subject matter: be it the rigging on a sailing vessel, waves crashing on the shore, still life, florals, landscapes or the human form.
Those that would lead us to believe that observational skills are all one needs to translate the visual universe into anything that resembles art are much mistaken unqualified false phophets or all three.
There is an enormous gap between painting a picture and creating a painting. If your would be mentor tells you to copy something and leaves the room cancel the check.