This might well turn out to be a wonder drug. If so, imagine the luck. Rampant Wuhan flu pandemic, no treatment, no cure. By a stroke of luck we happen to be sitting on a universally approved, heavily stockpiled, worldwide answer.
PLEASE NOTE FOLKS,the caveat:
The advantage of hydroxychloroqine is its potential reduction in length of stay, reducing the burden on the hospitals.
I hope it also helps in significant reduction in mortality (especially for the very ill ), but this widespread usage still needs to prove that.