Underdiscussed: The biggest difference these keyboards make: adding additional keys for the thumbs (replacing the unnecessarily large spacebar of traditional keyboards).

This allows the hands to do more with the keyboard while resting the hands on home row. -- For users comfortable adding a bit of complexity for the benefit of increased expressiveness (e.g. vim users), having extra thumb keys allows bringing the full functionality of the keyboard to within reach of the hands on home row.

For me, I think that these keyboards fix many silly design flaws of the traditional keyboard makes them interesting enough to be worth using.

There's a lot of fun to be had by replacing the spacebar with four keys.

Mine are tab, esc, space, backspace... plus layer shenanigans (https://configure.zsa.io/planck-ez/layouts/jDnba/latest/0)

A split keyboard does a good job of enforcing stricter adherence to the home keys so you end up getting quite accurate at the special functions too since everything is within reach. I think extra thumb buttons on a non-split keyboard gets you all the same benefits, I'd love to see more boards explore that.

Programmability is really an awesome feature for this very reason. Even with a traditional layout, you can be really creative and improve the ergonomics: tap/hold mod for the spacebar, remap caps lock to do all kinds of stuff...