perk vs benefit

perk and benefit both are nouns.

Word	Noun	Adjective	Verb	Adverb
perk	Yes	No	Yes	No
benefit	Yes	No	Yes	No

As nouns, benefit is a hypernym of perk; that is, benefit is a word with a broader meaning than perk:

perk: an incidental benefit awarded for certain types of employment (especially if it is regarded as a right)
benefit: financial assistance in time of need

perk (noun)	benefit (noun)
an incidental benefit awarded for certain types of employment (especially if it is regarded as a right)	something that aids or promotes well-being
	a performance to raise money for a charitable cause
	financial assistance in time of need

perk (verb)	benefit (verb)
gain or regain energy	derive a benefit from
	be beneficial for