Well, for the first time ever, I have registered for DSC and actually booked some flights. Not sure that I its going to make much of a difference for me in terms of SC earning, however ...
I had two return Classic Rewards bookings for later in the year so I thought I would take a look and see what might be available for rebooking the same trips under the DSC promo.
Trip 1 was able to rebook with a $68 net refund, and a net cost of 6K points, but more friendly times. So I was happy to "pay" 6K point, and get a refund of $68, and a net gain of 56 SC. But the major benefit for me is the more friendly flight times.
Trip 2 was able to rebook with a $67 net refund, and a net cost of 14.6K points, but significantly more friendly times. direct flights both ways rather than a connection in the outbound, and a net gain of 48 SC. The change to a direct flight outbound was a Classic Plus bookings, but at a reasonable points cost.
But the outcome of earning an extra 104 SCs for a net cost of a little over 20K points is poor value, especially as those SCs will be unlikely to make any material difference to my status now or any time in the future. I will receive a net refund of $135, which is nice, but hardly worth the forfeit of 20K points, But I have found more friendly flight times for all sectors of both trips, so that is the major win for me - the $$$ refund and extra SCs are secondary for me.