Personally, while I have never once used the touchbar, I do think the ability for apps to display contextual function keys has a lot of use cases. I would be happy if they released physical keys with little oled screens on them, like that old Optimus keyboard. Apparently it was garbage but the tech has come a long way in ten years.
I think that one thing holding this back is the lack of a desktop keyboard with a touchbar display. If there was a normal sized keyboard where you could have a full keyboard and a TB display, that would help give an incentive to have more touchbar apps like pock.dev.
Unfortunately, so many people hate the current version of the touchbar that there hasn’t been much innovation in this area.
The problem with the touch bar is that you have to look away from the screen to use it. Physical buttons would allow you to touch type, and I don't think it's a problem to scan the keys a few times when you start using a new app. In that sense they are just as discoverable as keyboard shortcuts. You look them up a few times, and eventually you use them without thinking about it.
Interesting, I've been wondering for years why nobody makes e-ink keyboards. I'm old enough to remember the $1,200 Optimus keyboard that had OLED screens in each key. Everybody wanted one, but then it turned out they were total shit to use. E-ink should have far fewer challenges than oled screens though. Just a bit of feedback: your product page doesn't tell me anything about the hardware design. I would want to know what kind of switches you are using, materials, travel distance, tactility, etc before I would consider buying one. You might want to include some detailed technical specs on another page if you want to attract the hardcore keyboard nerds. While they aren't a large market, they are influencers. I'd also like to see some video of the keyboard being used before I plop down $200 on a preorder.
