Panel marketing leads with the numbers that are easiest to maximise in a lab. Peak brightness is often quoted for a small highlight area held briefly, while full-screen sustained brightness may be a fraction of that figure.
Contrast does the heavy lifting
Static contrast, the ratio between the brightest white and darkest black a panel can show simultaneously, is what makes an image look deep or washed out. Local dimming improves this in scenes with clear separation but can introduce visible halos around bright objects on dark backgrounds.
Motion needs consistency, not a single number
A single grey-to-grey response figure hides variation across the transition range. What you notice in use is whether response stays even across brightness levels and whether overdrive introduces overshoot artefacts. Look for reviews that publish response across a full transition matrix.