To me, OLED being self-emissive is a far bigger deal than the contrast ratio. With LCDs, even the laminated ones in MacBooks, you get backlight shimmering, bleed, halos (especially with Mini-LED), and general inconsistency. With OLED, the pixels are a single, nano-thin layer, the display looks directly printed onto the surface (because it is), there are no backlight issues because there's no backlight, and there's no polarization or enclosure to create viewing angle artifacts. (Note: QD-OLED is inferior in this regard, especially with ambient light, but that doesn't bother me that much; WOLED however is trash.)
The OLED iPad Pro is one of the best screens I've ever seen, besides the awful pixel density. Even if deactivated pixels weren't fully dark, it'd still be far superior to any LCD.