It's not an unrealistic deduction.
Here is my scenario, my dad picks up 4 kids after school, and drives them for less then 5 minutes. These aren't adults, they are kids 2-6 years old.
I have a Y, and I would never consider getting a 7 seater as there is no way that is functional. The X is a good bet, but it won't handle as well as the S.
The jump seats, especially rear facing are a perfect match for a 5 minute trip, especially due to the harness.
Anyone with lots of kids would know that putting in 4 child seats in a Y type of setup wouldn't work, they can't fit, and you can't get in the vehicle without removing a seat or thru the trunk. So the rear facing option is a genius option really for super short trips such as this. It's likely with the Y and the X as options this may never happen.
This setup is no longer required for me in 5 years, but 5 years is a long time to need a specific solution.
After that they can be folded up and not used, or sold if they are transferrable to another vehicle providing they allow for it to be a retrofit to the next guy with the same unique problem.
I should also add, my dad likes the S, hates the X.