When Google introduced that button, I'm aware of some commercial sites that didn't use DRM and saw in the region of a 500% increase in the number of paying users grabbing whatever they could rather than paying for further views, continuing subscriptions, etc. Typically they soon implemented alternative methods of serving their videos, and the problem then disappeared again. It's a myth that such measures don't reduce piracy. They may or may not eliminate it completely, but piracy is not a binary problem and even eliminating a large amount of the casual piracy can be highly beneficial. Equally, even a significant incentive inviting casual piracy that was already possible but was not actually happening can be very damaging.