What you see above is an Iris. The Iris is a unique mechanical keyboard sold by Keeb.io. It is named after the goddess of rainbows because of the curved shape of the circuit board. The story behind the keyboard is neat, you can read about it here.
The most obvious difference between an Iris Keyboard and most other keyboards is it's chopped into two pieces. These pieces are connected to each other by a TRRS cable, then to your computer by a usb cable. As long as everything is connected, it works just like a normal keyboard. So if it works like a normal keyboard, what's the point of splitting in half in the first place? I'll explain.
Modern keyboards are built around pretty much anything but comfort. Most keyboards get general design from typewriters. Typewriters were built to feed a piece of paper through, but they were also complex and heavy. Making them any larger would have been more expensive, so that's where we get the general size of keyboards from.
Fun fact: The way keys on modern keyboards don't line up in rows is also a carryover from typewriters. Typewriter keys had to be offset because they worked like physical stamps. Now that keyboards work with electric signals, there's no practical reason for keys to be staggered anymore.
The problem with the size of typical keyboards is: it makes no sense.
It is impossible to use a typical keyboard ergonomically. You either need to angle your wrists into the center of the board, or strain your wrists to type parallel to the keys. Both these position are bad for your wrists.
A split keyboard, as you might have guessed, mostly fixes this problem. It lets you position the halves of your keyboard as far apart as you want so that your wrists can stay neutral (for truly neutral wrist position, we need to tent the keyboard too, but that's for another article).
Separating the halves of your keyboard also makes maintaining a straight posture much much easier. When we reach in to type on a normal keyboard, our natural inclination is to pull our shoulders forward and slouch. Split keyboards let you keep your shoulders and chest open.
Let me get why you might not want a split keyboard out of the way first. It's got a learning curve. Especially if you are very used to typing on traditional keyboards, maybe with a few bad habits around which fingers hit which keys, typing on a split keyboard will be slow going at first.
There's not necessarily one correct way to type, even with a split keyboard, but chances are you'll still have to adapt. It will take weeks of practice to get back up to normal speeds. If you're lucky you can afford to take the productivity hit and dive headfirst into just using the split keyboard, but you'll probably have to use it for a while then switch back to a normal keyboard to get some work done until you get more comfortable with it.
Worth it? I think so. I'm relearning to type on a split keyboard right now.
I had to assemble and solder this Iris keyboard myself, which I acknowledge is not for everyone. If that is a project you'd like to take on, check out Keeb.io. If not, I recommend the Moonlander or Microsoft's Ergo Keyboard if you're on a budget.