to add to the other comments's explanation: imagine you have algos A and B, where A is better than B your top competitor has algo B, and everyone else has C

to add to the other comments's explanation: imagine you have algos A and B, where A is better than B your top competitor has algo B, and everyone else has C if you release B to the public, now every C becomes a B and competes directly with your strongest competitor. (pure speculation)