My vim muscle memory has paid off more for me than my emacs muscle memory. Emacs was the better editor, though. Anything that doesn't have Vimscript is an automatic winner IMO.
I use ^a to go to the beginning of a line and ^e to go to the end nearly everywhere. Many Emacs keystrokes are so pervasive that they're not often thought of as Emacs keystrokes.
Strangely enough I tried using vi mode for readline and hated it even though I use them constantly in vim. I just hated having to switch modes on my terminal
The thing about emacs and muscle memory is that all of the standard emacs keyboard shortcuts are also the standard all throughout the Mac operating system, so when you’re writing in text boxes in a webpage, writing in a Google doc, anywhere you type, throughout macOS, it’s emacs shortcuts. That has a lot to do with building my muscle memory.