Why do no split keyboards have symbols on the keycaps? What happens when you forget where a key is that you don't use often, do you just have to press keys until you find it again?
Partly because they're a niche product and making legended keycaps is more expensive, and partially because ergo layouts are so varied that it's hard to accommodate everyone. Especially if the keycap profile has different shapes for each row so they're not entirely interchangeable.
There are a few low-profile legended keycap sets around but they typically only cover the "top" layer, which is the easiest to remember anyway. If you want legends which show every function of every key you'd have to get them custom laser etched to match your personal keymap.
You can buy ZSA split keyboards with labels on the keycaps. Its great while you are still learning to type on these rather exotic keyboards. As you get more proficient, you start to rely more and more on the "central" keys (using layers toggles to put, say arrow keys on the home row). Muscle-memory is often more than enough.
That said, I have kept the number row labelled. These keys are not obscured by your hands and they can give you the necessary frame of reference. The ideal trade-off for me.
When I forget where I've stashed a specific symbol or similar I just check the Via QMK configuration tool, similar to when you're trying to learn the shortcut keys for a piece of software. Eventually it's muscle-memory, but it's nice to have a reference guide whilst you're building it.
Software is as critical as hardware: The UHK supports holding a key down to select a different keymap layer, then using the other hand to tap a key in that layer. While few people learn many-key chording, "one finger each hand" is every bit as easy as ordinary typing, with practice. This supports an n^2 expansion in effective keyboard reach. I'm surprised this isn't the norm for selecting Chinese/Japanese characters.
The question is: How well? I'm not entirely happy with my QMK firmware implementation. Tap-hold is the antithesis of n-key rollover; one needs to learn to properly nest key-down, key-up events. It's easy to switch from a clarinet (cleanly cover holes) to a saxophone (slap pads), but hard switching back. And we've all learned to type like we're on a saxophone, relying on n-key rollover to cover many sins.
I now use QMK firmware with Hasu controllers for multiple Leopold FC660C keyboards with Topre Silent 45g "rubber dome" key switches. After trying dozens of mechanical key switches, I found that nothing feels like a Topre switch.
And here's the kicker: The physical form factor doesn't matter so much if your fingers rarely go far from home row, which is what tap/hold facilitates.
You can modify the uhk firmware quite extensively with the included Agent application. I typically stick to holding a keys to access different layers, but you can also double tap them to make it stick to a new layer. I only rarely use that functionality myself tho.
Being able to modify each button, in each layer has it's downsides tho: if I'm ever on a keyboard other than my own, I can barely type anymore!
I've edited away my most common typos on my keyboard layout, eg the key that's normally caps lock is just another shift key in my keyboard, since I find only ever use that key by mistake.
Now when I'm on another keyboard I hit it all the time, since I'm so used to it not being a problem
Realistically you've got about 50 or so keys and you are using all of them all the time, so you're not really forgetting where anything is. Many also customize where symbols, media keys, etc., are - so they are positioned where it makes most sense to you. Outside of maybe a 2 week learning period I haven't needed to look up where a key is at all
The other thing is that many keys will have multiple functions - so what do you print on them? e.g. my j key also doubles as # and the down key. Some are maybe even more frequently used key combinations, e.g. I have a ``` and a => key
It's just kind of unnecessary when you can just learn the layout. It's not a big deal, I've used blank keycaps for almost two decades across multiple different layouts.
Just friction. All it takes is commitment to a particular keymap and few minutes on a laser engraver, but that commitment is not insignificant to builders.
when you have so few keys, there are none that you don't use often. When you customize your layout, you have keys that don't really correspond to caps anyway, and you may want to mess around with their values as you get used to it. Typed from my Iris with key caps from an Apple Extended Keyboard II that look nice and don't really tell the whole story for each key they're on.
Honestly, for mine it was because I didn't know what I wanted the keys to do when I was making it. It took a few months to settle on a layout, and even now I might still change it with usage.
