I personally think there are benefits to the institution. As head of state they can do things the Prime Minster cannot. It provides stability.Honestly, I think Great Britain should take the opportunity of the Jubilee to say: "Thank you for your long & successful service, Your Majesty, but you are a difficult act to follow, and let's allow your reign to stand as the best possible end to this instititution." and simply abolish the whole thing.
I don’t see the benefits though for Caribbean countries