So no one seems to want to explain why dark mode is better than anything available now. Meaning it is useless but looks a little different.
The main thing is that allow to reduce the amount of white.
Yep, is sound dumb... but it matter.
A very
bright screen tire the eyes faster.
High-contrast is better too.
So, dark mode, apart for be more cool, is better for people that stare at screens at mostly static things FOR LONG TIME.
You heard in the keynote how is say that exist a group of people that will love this much more than others:
DEVELOPERS. Is the same for anyone that work a lot with text.
The thing here, is that you need to combine things a little to make the thing actually better: Reduce glare, reduce contrast, reduce
brightness (<- probably the single most usefull thing!... and then, you know? you can make fonts larger, idiot! is the way!).
And then you spice things with a dark background and things will feel way better. After a lot of time on white, you eyes will thank you.
This thing is so obviously better for us (developers) that in the moment you learn (by osmosis, mostly) you wanna do this for all tools. Terminal? Black. Code Editors/IDES? Black Themes. A lot of extra tools for developers come in black.
Other group where this is usefull as anything related with graphics, 3d, animation, photography.
Why?
Light.
White cause a certain extra "light". Imagine that you put a extra lamp around a photo. Is "wrong". But a screen is amazing and
YOU CAN MUTE THE EFFECT. Is less distracting. And more neutral. This is what I get from my brother (3d artist/pro photographer). It learn it from others (in fact, I remember was him that ask me the same question.. and later get a more proper response from others prfesionals. I don't remember all that details)
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A simple test that show how much better things go is try to do a presentation with a proyector. ecause them have less graphics quality (ie: in the moment of the projection) is easier to see that show code on white is less good than on dark. Dark read WAY better, specially for people more far in a room.
Also, the syntax-coloring "pop out" more.