Do you mean "critical" literally or hyperbolically? I disable ligatures in any editor/terminal I use, because I find them confusing and want to know what the actual characters in the code are.

I think there are still dev environments where ligatures in terminals are not so critical. Especially those of devs who do not use in-terminal editors for most of their editing.

I use and love ligatures, but calling them "critical" is weird. I'll have to admit that they're the reason I don't use alacritty, though.