Outside of skimo racers, probably none.
Although many people have used their phones to post their outrage on Facebook about how all those unknown-to-them Recon LT owners have had to use their phones...

I bricked my new Di2 bike last year when I finally capitulated to the E-TUBE app's insistence that I update the firmware.
Took my LBS about a day to fix it, and that was with a mechanic who used to...

The switch problem was definitely a ... problem.
However, both Steve Achelis and I spent a lot of time testing that switch, yet we never experienced any problems.
And both of us are pretty picky...

Given that updating the firmware took me about as long as writing this sentence, sure doesn't seem to be all that big a deal.