Question

What brightness do I need indoors and outdoors?

Indoor walls are usually run well below their maximum; outdoor walls need enough brightness to hold against daylight and auto dimming for the night.

Measured, then dimmed

A display is specified at its peak brightness and run below it. Running at maximum all day shortens life and washes out the room around it.

Outdoors is a daylight problem

A facade or billboard competes with the sun and the sky, so it needs far more brightness than an indoor wall. The same wall dimmed at night stops glaring into the street.

What the specification should say

Peak brightness, the dimming range and how brightness is controlled belong in the specification. A single nits figure on its own does not say how the wall behaves.