In Greece: it was very much a mainstream term from Mediaeval times right through to the early 20th century. It was also used to refer to Greek Catholics; hence the classic song Frangosyriani “Catholic girl from Syros” (1932), from Markos Vamvakaris, himself a Catholic boy from Syros. The conflation of Western Catholics and Levantine Catholics makes sense in the context of the Ottoman Millet system.
Nowadays, I’m probably the only person who uses it with any contemporary reference, because I’m an antiquarian like that. Greeks now consider themselves Westerners, and have for a while; so they have no use for a term Othering the Westerners.
But as a historical reference, whether to crusaders, or to the Latin Empire of Constantinople, or to the confused relation between Greeks and Philhellenes during the Greek War of Independence, Greeks will still get it.