That's what I wrote. But they go verrrrry slowly and that is hardly relevant to the carrying of the energy. A Bicycle chain also 'goes round' but the energy gets from foot to wheel much quicker.They actually do 'go round the circuit'. I think the term is called 'drift flow' or something (now I'm curious. what exactly is the term?), but thats not important to the circuit, so yes, considering them the medium of a wave in the circuit is a good way of looking at it.