I actually bought myself an ergonomic keyboard months ago that does support tilting it in the other direction, with a curved wrist rest to help.
It works quite well, but I also like the concept of the one I built.
I's like to tilt it to make it more comfortable, if it turns out I like using it.
From what I understand, you can have all the keys you need on a keyboard like that, but it requires muscle memory of key combinations, and I do not know yet if that's for me. I'd have liked to start on a board with more keys, but it's expensive just to see if it suits me or not.
I can also see it being useful in VR while playing games like Elite Dangerous, to have one half per arm on a chair with a HOTAS setup.
It's definitely a niche thing.

edit: just read your other comments and I think you should chill a bit. I see these things as specialized and personalized computer input interfaces. People are different and input methods should be too. It might not fit your bill, but it might for some people here or maybe they like experimenting to find what works for them.
I don't want this to become a VI vs Emacs flame war analogy.