In the hacker world, you ideally have something that is both: you can't live without it, and everybody that tries to use your computer runs away in tears.
One design that I really can't stop thinking about is how Plan9 lets you just draw a terminal window any time you need a new window, and when you run a command, it just turns into the program.
Something like that would probably melt people's brains.
Sadly, I'm only 2/5 out of this: tiling vm (sway) and arch. Although maybe having a custom script that remaps a bunch key events (to create a multi-language layout and macros for sway) counts as a weird keyboard layout? My colleagues probably aren't able to type on it, at least. 😄 Also, I was trying to learn Colemak, but haven't managed yet.
A split keyboard sounds nice for programming! But I'm afraid it'd be quite annoying for drawing things (one hand on mouse/stylus, other hand for hotkeys). Maybe having one with lots of buttons on the left side that can be remapped would help? But that kinda defeats the purpose of having it split.
It looks like a lot of the split keyboards are also fully progammable (at least mine is), it seems reasonable to have a layer with all your bindings for an application on one hand, and maybe backlighting on that layer to highlight where the keys are for it.
I personally keep a drawing tablet between my split keyboard, but I don’t do a lot of actual drawing with it (mostly just osu).
The best benefit as far as programming that I think I have is having all of my punctuation either within close reach from the home row, or on a separate layer in an orderly fashion (ie matching brackets are placed next to eachother).
And although I don’t have a physical mouse at my desk, I am able to use my keyboard to move the mouse for applications that abolutely require a mouse.
Here is my layout if you want to take a peek at it. It has a few weird things like some redundant keys. Just haven’t figured out what I want to replace some of them with yet.