From my own experience;
I have spent years working on my Q. To satisfy myself, my family, and others (in that order)
Starting last year I decided to try my hand at competitions, to see where my own Q stacked up against the "pros"
I am now working on learning what judges like, and am finding that it depends almost entirely upon regional preference.
While any particular CBJ may have been taught to judge by the same criteria as other CBJs, individual judge's own opinions are what drive the score, and opinions are subjective.
Bottom line: i will continue cooking what I enjoy, and will tweak my recipes to (hopefully) suit the judges that particular day.
So the question; which one to we learn to cook for first? My vote went for myself & others.