Hi Stuart,
This only works when applying attributes to specified clips within your project. I think Matthew was after the same thing as I was, which is to be able to batch modify the ‘sequence settings’ i.e. compressor, frame size, pixel aspect etc – for several sequences rather than modifying clip settings.
There doesn’t appear to be a way to do this other than loading sequence settings one sequence at a time. The copy attributes though, as you mention, certainly does work for multiple clips but again as you rightly state, the final result of this will depend on the sizes/aspect ratio of your copied clip and the clip(s) you wish to paste to.