strong point vs long suit

strong point and long suit both are nouns.

Word	Noun	Adjective	Verb	Adverb
strong point	Yes	No	No	No
long suit	Yes	No	No	No

As nouns, strong point and long suit are synonyms defined as:

Other synonyms of strong point include forte, metier, speciality, specialty, strength, strong suit.

strong point (noun)	long suit (noun)
an asset of special worth or utility	an asset of special worth or utility
	in a hand, the suit having the most cards