KoC in parishes I have been in is like the Masons for Catholics. They run a lot of fundraisers such as fish fries in Lent and spaghetti dinners the rest of the year. They participate in special Masses like when Padre Pio’s relics or the Bishop come around. They also often participate in community events like having a booth at the local street fair to raise money for the Church or for charity.
Edited to add, I forgot the insurance part though I’m not sure that is so key anymore now that people have lots of places to get insurance and widows have better support.
And they do often have a social/ prayer club function as well so men can hang out with other men from their parish.