I'm not sure what is the difference in behaviour between
switchport block multicast and
storm-control multicast and I don't think cisco elaborates the difference very well in their documentation, other than the fact storm-control grants you levels of control, but for this case, suppose the storm-control only lets you pick up 0 or 100. How is it any different from switchport block, for instance?
Update: I accidentally wrote "switchport block unicast" when I intended to write "switchport block multicast".