A) I like being able to work on my bike myself
B) I like being able to afford replacement parts
C) I need to run a gxp crankset for stages anyway
D) I have a SRAM red group just sitting there (see also point C).
E) I don't want to have a bike I need to charge or run a diagnostic on. Its a bike ffs.
F) di2 is nice, but not nice enough to justify ignoring any of the above. Its just a luxury; and one that doesn't make you any faster.