The advantage of the U.K. plug is that live pins are physically blocked and only released when the Earth pin is present. This is why the Earth pin is slightly longer on U.K. plugs and why insulated devices have a plastic Earth pin rather than no pin at all. The advantage of this is so you cannot jam things into them (either accidentally or intentionally) without the Earth pin. Thus making the plug much safer.

I’ve found U.K. plugs to be much more secure inside the socket too. US plugs often come away from the wall when there is a little bit of weight or tension on the plug. U.K. plugs require a great deal more pressure to come loose from the socket.

If I were to bring this back to types I’d say one needs to evaluate what the requirements are: safety or convenience.