Well, in vanilla vi - I'm not sure (quite frankly, anyone who stands by vanilla vi as a great way to edit text is fudging insane). In typical VIM installs, ctrl-c and esc are aliases of one another.

Yeah, I meant vi(m)-mode in Bash/readline as mentioned in this discussion. When editing or correcting a command it may be inconvenient to destroy the whole line when switching to movement-mode (which does not happen, if it is not ctrl-c).