Wait for the slo-mo recaps at the end that show him ripping through the tech sections faster than any human should be able to.
@Ryan, there’s not a lot of shifting going on, but the gear you use coming out of the start gate and what you use when you’re trying to hammer towards the finish line are absolutely different. And when hundredths of a second can matter, having those gears will matter. In addition, with limited practice runs, wasting one or more on gear selection is going to be practical. Lastly, you still have to deal with chain tension on a full-suspension bike somehow.
@AlanM, I think a chain tensioner would solve the rear suspension concern. Do you think the lost weight from dropping the cassette/shifter/derailleur would shave time though? Admittedly I do not ride DH, nor do I compete professionally. I make these inquiries from my arm chair.
I do ride my MTBs regularly though! 😉