>
>  I can see
> someone doing
>
>     C-o foo bar
>
> but I don't see the benefit compared to
>
>     foo bar RET
>
> It probably comes down to habit, but I'm hoping there's more to it
> than that.
>

I have realized I want to add more text somewhere in the text:
----------------------------------------------------------------------
This is the beginning of the text before the insertion. Here is the
end of the text, after the insertion.
----------------------------------------------------------------------
Point is on "H" in "Here". Before typing the new text I do C-o to get the
continuation out of the way while typing. I wouldn't do that if I'm just
adding something short, but if I'm adding a longer text I would.
In programming I would also do that if adding something longer or something
complicated. It feels better to be at the end of the line when adding text
than to push text in front of you, which can look a bit disturbing,
especially if it is long enough to be broken over to the next line.

I guess this is mostly by habit, but I see at least some advantages of
entering text at the end of the line. Then it's easier to C-e back to point
of entry if I go back to revise something just written, and I can use the
special case of C-t  for quick fixing. Also pushing text in front of me
will be a problem for ispell-word and other commands that look up the
current word. I could make sure to position myself before a space to avoid
that problem, but that would be an extra step to make where just C-o is
simpler.