I've thought that too, especially on the old 6spd Slushmatic that haunted the E90 generation. On the 8AT, particularly the DCT quick Sport Auto, I can perhaps see it making more sense as it can skip gears and so perhaps this kick-down notch is the thing that really gees it up to get to the lowest gear as quick as possible. Maybe it's purely for driver satisfaction? But yeah, I completely get what you mean...
I was driving an E63 AMG recently and its kick-down notch didn't seem that operational really - it would just continue to pull from medium rpm to redline without dropping 1 gear as I expected it would. Mind you, that's what >700NM is for.
EDIT: Just as a side note, my E90 LCI 330d 6MT had a kick-down notch. Obviously, completely redundant but it still had one. However, it went in for service (about 60,000mls I seem to recall) and it came back without one. Don't know if I got a new accelerator pedal unit or what. I'm pretty sure my old E60 520d 6MT had one too.
2006 BMW E60 520d SE 6MT
2009 BMW E90-LCI 330d SE 6MT
Current: 2012 F30 328i Luxury 8AT
2015 Audi A6 Avant Ultra, Black Edition (sorry!)
Last edited by SomeRandomer123; 01-16-2014 at 11:02 AM.