Never have I seen a bigger load of after-the-fact justification since the last time George Lucas ranted to Entertainment Weekly. Byrne, you stole that idea from Alan Moore and we both know it, now fess up!
Actually, the aura predates Moore back to the Silver Age Ultra Boy in the 1960s as I mentioned earlier on this thread.
Possibly, George Papp or Jerry Siegel himself came up with the aura for Ultra Boy as to why his costume remained intact when using super-speed or invulnerability. (Jo was a Siegel creation, BTW.)
I'll see what I can find out but I know the aura way preceded both Moore and Byrne or any other contemporary writer.