I think you missed the point where someone may have more than one keyboard and switching between is an necessary pain. Yeah If you want to train yourself to use a keyboard layout no big deal but if you're like me and you switch from server to server during the day having a consistent keyboard layout means I can thing about what I'm doing and not worry about typing.
Switching to emacs may have some productivity gains for you that make re-training useful. There is no added benefit for me to learn to type again.
I switch from EMACS to applications with CUA mappings to websites with their own mappings to graphics applications where moving by words and lines doesn't even make sense. Then there's PowerShell.
I don't bang with gas pliers or grip with a Torx screwdriver. Tools are rigid. My brain and body flexible. But if I was switching machines all day I would bring my Microsoft natural ergonomic 4000 with me.
Switching to emacs may have some productivity gains for you that make re-training useful. There is no added benefit for me to learn to type again.