My local beach is under the plow. Checked the plowed areas but not to many signals. Plenty of signals from the unplowed wind
swept areas. Managed to find some change and a nice 1949 dime.
I would think that the purpose is to run everything through screens to remove the refuse left by people. Similar to derockers used on some farms, such as the several I worked on as a teenager in the ‘70s. Faster, cheaper, and easier than paying to send a thousand people to the beach with garden rakes and trash bags.
Last weekend there were these big piles of sand on the board walk. Actual the sand was all over the board walk and the plows were pushing it in to plies. I thought the storms that week sent the sand onto the board walk. Don’t know.