expedience vs vantage

expedience and vantage both are nouns.

Word	Noun	Adjective	Verb	Adverb
expedience	Yes	No	No	No
vantage	Yes	No	No	No

As nouns, vantage is a hypernym of expedience; that is, vantage is a word with a broader meaning than expedience:

Other hypernyms of expedience include advantage.

expedience (noun)	vantage (noun)
the quality of being suited to the end in view	the quality of having a superior or more favorable position
taking advantage of opportunities without regard for the consequences for others	place or situation affording some advantage (especially a comprehensive view or commanding perspective)