I don't understand this at all. Maybe if they were working under the bridge or over the side of the bridge a skiff would be beneficial. But they were repairing pot holes on the road surface. I think they are just looking to blame someone for something and this was just a terrible accident.
I drive the causeway every day - they seem to do work on it once a month or so - I’ve never seen a boat in the water but now I’m wondering why not
While it’s unlikely someone’s going over the side, the odds certainly aren’t zero, having a boat in the water seems a reasonable safety feature