It's not much extra time, and I'd say the quality difference between fermented and unfermented is exactly what I'd expect it to be, as a brewer. 
My guess is that some of the quality improvement in the 2-day dough could be achieved on other ways, like investing in super fine "00" flour and things like that. In the 2-day recipe, I didn't see any difference with the 00 flour, so it may just be that the extra time helps coarser flour take on the hydration better. Pure speculation, but I almost always know I'll be making pizza in two days, so the 48-hour cold rest is just SOP now.
My guess is that some of the quality improvement in the 2-day dough could be achieved on other ways, like investing in super fine "00" flour and things like that. In the 2-day recipe, I didn't see any difference with the 00 flour, so it may just be that the extra time helps coarser flour take on the hydration better. Pure speculation, but I almost always know I'll be making pizza in two days, so the 48-hour cold rest is just SOP now.