I gotta call bullsheet here, Liam.
I don't follow the logic in this 'either/or' type of statement. I ride an alum hardtail, so I am frequently messing around with tire pressure (especially the rear). My goal is to get a balance of sufficent traction, a reasonably cushy ride, and low rolling resistence, in that order.
On the techiest of trails I typically run around 25 psi. But even when I 'air up' for fire roads or buffed singletrack I seldom go as high as 50 psi. Traction begins to suffer at these higher pressures (2.4 Mutano on the rear).
I guess that makes me a lukewarm, non-envelope-pushing fence-sitter.
Oh well, to each their own...