[ChrisAtWork]

That particular example was chosen not because of OData, but because it required someone to type in a horribly long set of alphanumeric codes.

There's no way a human can effectively type that, nor is there any real way to look at it and figure out what it's doing. That the URL happens to use ODAta (because that's what Exchange does) is not really relevant.

The overriding factor, as called out in the doc, is that URLs should be human understandable. That's not to say canonical id's can't be used, but a big base64 encoded string is not recommended.