I get using vim on machines were Neovim is not installed, same way I use vi when vim is not installed. But why switch between the two on your personal machine?
No-Config neovim works preetty much the same as vim, except with better defaults.
Neovim doesn’t have :smile.
I switched to neovim before vim8 came out, mostly due to async support.
And after a while I ended up with building an async code completion plugin - nvim-completion-manager