Apple claims on its website to support 1,000 nits sustained brightness and 1,600 nits peak brightness. If in reality they can only sustain 500 nits brightness, that's probably a disappointment to people who spent extra on the newer, fancier display in the hopes of working on the laptop outside.
If they can't sustain their sustained brightness, that might even be false advertising.
Yeah, I'm people; got a 14" MBP expecting to be able to ramp up the brightness, and was surprised to find it caps out at exactly the same brightness as my previous 16" Intel. I think their marketing claims here are extremely deceptive. Apple should be above engaging in such shenanigans!
(Nevertheless, still super happy w/ the computer as a whole; it's an amazing machine.)
If they can't sustain their sustained brightness, that might even be false advertising.