I also access using the Plat but, I will say having the lounge access does play a small factor when choosing who to fly. Given the fact that i'm AUS based and hate flying AA and dislike WN, I'm either on UA or DL. All things equal, if I have to have a layover I'd rather have a quiet space to relax and work. Plus the AUS SC is huge for an outstation (Built when DL had it as a focus city) and almost never crowded.