Zcash was using it for a purpose where waiting a week or two to validate the random beacon was fine - it was a one-time calculation required by the mathematics

Zcash was using it for a purpose where waiting a week or two to validate the random beacon was fine - it was a one-time calculation required by the mathematics of their trusted setup. But yes, you are absolutely correct that for many applications that isn't feasible. Your idea re: online gaming is a good one!