I am surprised to hear of basements on a barrier island (peninsula). A basement would seem to be a near permanent indoor pool. Isn’t the water table near the surface in such a place?
My husband’s father has a home in NJ on Long Beach Island (home of Seaside, aka Jersey Shore show).
He has a basement, a small one but an entire floor below the home. It’s always dry but for the occasional huge storm, and not all storms, either. It’s where their washer/dryer, water heater, etc are.
Not all homes have a basement on the island but many do. The home was built in 1927.
He lived across the street from the bay and I only remember him flooding once, during Hurricane Donna.
Some basements have apartments. I never cared for them much, they always have musty smells. This is a picture of the entrance to a friend's basement apartment. She lost everything. I sent her a check to help her get back on her feet.