fzf won't work in shell-mode as it does not handle curses-like apps. Thus, `ezf.el' avoids that problem by using Emacs as the fuzzy searching facility. To say nothing of the fact that this is a fine example to re-use for, similar, needs where you need to receive and send back information in an ordered manner.
(And helm is far more advanced than fzf is, as far as searching)
(And helm is far more advanced than fzf is, as far as searching)