> For example, you could add an alternative page called item2, and it would happily reuse all the resources of item just via relative URL resolution.

I don't understand. If you wanted, for some odd reason (you hate search engines?) for the same resource to have two URLs, you could simply do:

    app.get('/items/:itemID', itemController);

    app.get('/item2/:itemID', itemController);

Though that seems like a very strange thing to want.

> What does that buy us in practical terms?

I can crawl it, and expect to find different resources at different URLs, like every other news website.