long suit vs strong point

long suit and strong point both are nouns.

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

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

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

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