That said I used to use a lily58 and for me it was great. I have a lot of papers, notes and books on my desk. A small easily movable keyboard meant that i could have something between the keyboard halves, writing and reading without issue
I had initially thought that it'd be hard to use both kinds of keyboards at once, but my muscle memory for either seems unaffected when I use the other one.
The thing I thought was ergonomic BS was the benefits of columnar/ortho layouts; everyone talked about how your fingers just moved vertically and it was so much better for them, and I rolled my eyes. But dang if it hasn't proved to be meaningfully true for me, too -- when I have to type on a legacy keyboard, I can clearly feel the pain in my fingers. (The disclaimer here is that my fingers are totally screwed up; if you don't feel pain normally, this probably matters less.)