I'm guessing it'll have a similar phone app to the Zero. I quite often use that, sometimes foe stealth so i can have the FZ in my pocket and look like I'm doomscrolling and not sniffing the airwaves, and sometimes just because almost 60 year old eyes have a better time using my phone screen instead of the tiny/grainy FZ one.

Most of the power in a display goes to the backlight. Going grayscale and low res wouldn't save much at the same level of backlight brightness.