When the environment is adversarial, smarter than you are, and informed about your methods, then in a theoretical sense it may be wise to have a quantum noise source handy.
It can be handy even if it’s not adversarial, and even if it is equally as smart as you are but not smarter. Suppose you’re playing a game with payoffs (A,A) = (0,0), (A,B) = (1,1), (B,A) = (1,1), (B,B) = (0,0) against a clone of yourself (and you can’t talk to each other); the mixed strategy where you pick A half of the time and B half of the time wins half of the time, but either pure strategy always loses. This even though the other player isn’t adversarial here—in fact, his utility function is exactly the same as yours.
It can be handy even if it’s not adversarial, and even if it is equally as smart as you are but not smarter. Suppose you’re playing a game with payoffs (A,A) = (0,0), (A,B) = (1,1), (B,A) = (1,1), (B,B) = (0,0) against a clone of yourself (and you can’t talk to each other); the mixed strategy where you pick A half of the time and B half of the time wins half of the time, but either pure strategy always loses. This even though the other player isn’t adversarial here—in fact, his utility function is exactly the same as yours.