Different priorities. It's HARD to build an EV that combines max. efficiency with max. utility and pax/cargo volume - Tesla certainly hasn't done so. All design involves compromise. The e-Tron's profile obviously provides more usable interior space than a Model X. While the range is a bit short, for trips that require repeated charging the fact that it has low taper owing to the restricted SoC range should make it easier to use. And I believe the fact that the typical buyer wouldn't have to learn a lot about the effect of high and low SoC range on longevity but just charge the car to full and drive it to near empty like they'd do with an ICE is a good thing for mainstream buyers.
I thought GM was smart to do this with the Gen 1 Volt as well, even though the need to carry around extra unusable capacity lowers the efficiency. If BEV's are to become mainstream, they can't require buyers to learn as much about the car as denizens of sites such as this one typically do. No games of "20 Questions" to see if the vehicle is suitable.
Guy [I have lots of experience designing/selling off-grid AE systems, some using EVs but don't own one. Local trips are by foot, bike and/or rapid transit].
The 'best' is the enemy of 'good enough'. Copper shot, not Silver bullets.