Good points. I mostly use split keyboards to solve the arm problem, and there are staggered column layouts like the ergodox and friends that solve the finger problem (I'm typing on one now). And no, the staggering isn't for ergonomics, it was a limitation of mechanical typewriters[0] and it just stuck (hah) after that since it was what people were used to.

[0]: https://ux.stackexchange.com/a/40403