Originally Posted by
NCommander
I've only SDC'ed a few times, but I find it very helpful if a connection (esp. international to domestic transfers at ORD, where I book with extra time) gets in earlier, and I can standby for an earlier flights.
Also really handy in IRROPS scenarios when you get stuck somewhere overnight and end up on an odd-ball flight plan.
SDC is slightly different to standby. You are actually confirmed onto the earlier flight rather than waiting around for the standby to clear. And the OP is probably one of many who book the flight they want rather than booking a cheaper flight with the hope of getting the earlier flight.