In China this is generally played by men. In the 1920s and 30s it swept the NY Tenement buildings and was taken up by Jewish women.
My grandmothers both played several times per week. My mother played in a weekly game until she was 90. My MIL still has a Monday game.
My wife does not play, but both younger daughters have learned the game and play occasionally.
My maternal grandmother referred to the game as ‘idiot’s delight’
It is gambling for low stakes (typically $5 maximum loss for the entire afternoon or evening). It became popular as it gave housewives a chance to spend a few hours with other adults and not children or housework.
There is a National Mah Jongg League who prints the annual rules and lists of possible winning hands and payouts. They donate a large percentage of the sale of the cards to Jewish charities in the uS and Israel.