It is necessary that xfce-terminal supports displaying in fonts with ligatures. Not all users browse websites in "only latin" script. Terminal emulators are often used to browse the web with lynx, use vim for text files, writing emails, thus global fonts support become essential to be included in terminal emulators.
Hi, It's up to vte (the terminal widget) whether or not to support ligatures. See the following vte bugs: https://bugzilla.gnome.org/show_bug.cgi?id=781597 https://bugzilla.gnome.org/show_bug.cgi?id=584160