You haven't really learned anything until you have set it all down in coherent fashion in writing. You are forced to think harder, follow out consequences more rigorously, and to revise you r ideas more drastically in five minutes of writing than in a whole day of meditation.
Writing is the best, and probably the only, means of coming to grips with thoughts.
For a researcher or teacher writing is an indispensable skill. You will have to write for the rest of your life. You can no more escape it than a cowboy can escape riding a horse. If you are goo d at it now, work to become excellent. If you are poor at it now, work doubly hard to become excellent.