I have 75D. The one scenario I see where I wish I had the 100D which I have had a couple of times is travelling distances of one way of 90-100 miles somewhere.
To elucidate, recent trip to a beach town about 100 miles away. So right off the bat I need 200 miles at least which equals to 210 -220 or so to be on safe side. And if I ended up doing trips around the town would end up cutting it close. So I had to supercharge 30 miles into my trip to keep enough in reserve to be able to drive around town as needed.
I have had the above a few time where I have driven 100 or so miles one way. End up needing supercharging whereas with 100D I would not have.
I live in North east, so enough superchargers around for it to not make too much of a difference but still wish had paid 10000$ extra for a loaner/inventory 100D.