Paul -- I think that's definitely one of the reasons. Where I was fishing, you'd have a really rough time keeping your "working" line (floating, sink, whatever) from tangling in your feet, on rocks, into horseshoe crabs, etc. without it. The surf just knocks that stuff around. I made the mistake of dropping my working line into the water at my feet to grab some stuff out of my pack and when I went to retrieve it, I had the biggest mass of sea weed, line and debris I've ever seen. It took WAY too long to untangle it too -- very frustrating.
I understand that a lot of people use the big boat buckets too -- probably for the same reasons (tangles).
For casting, it seems to help keep the line from tangling on itself and you can shoot more line -- at least that's what I experienced.
Though I've had only 1 outing to SW, I would not recommend drinking while fishing these areas. I discovered 2-3 new ways I could probably kill myself sober out there, and I wouldn't want alcohol in the mix.
Gene