I have to agree with the question of SC devaluation. Whilst I'll happily take advantage of them, I can't help but feel uncomfortable about DSC's. I have always felt that the 1.5 SC's offers were possibly more prudent. DSC's risk creating a lost zone of dedicated customers.
Consider a loyal customer who flies interstate most weeks. 10 SC's each way, every week. Gold customer, and well earned lounge access. To move up to WP, they have to book at a higher class, or fly further afield. With DSC's, these customers move up to platinum. Even if they only just made 700 SC's, double this and you're WP.
Now consider a more serious customer, knocking up 1400 SC's a year. To do this without help indicates a good customer. What do DSC's do for this customer? Help them to LTG but once that's achieved? If they are not able to make the big leap up to P1, the reality is that their status is being diluted. The logical thing for them to do is to use DSC's to retain their status earlier, then chase status with the opposition. The same argument applies to those who can make P1. Retain sooner, look elsewhere.
I understand the use of points offers to help cash flow. Points have a value than can be quantified and assessed. SC's are far more complex and it's possible that too many DSC offers may actually hurt the bottom line long term.