I've found that fzf has replaced all uses of find for me except in scripts. fzf has the benefits of being bound to a single key binding and showing me results as I type, rather than after the command runs.
You're right that fzf doesn't replace find. Fzf is just an interactive, filtering tool. You can pipe anything into it. find is a common way of populating it with data.
I suspect the GP meant that fzf replaced the pattern 'find |xargs $binary' for small interactive use cases. It's much nicer to do '$binary <invoke fzf>'. I use fzf the same way with key bindings to select directories and files powered by find.
