XML Torrents?

At the risk of getting stoned for heresy ;) I'm wondering why .torrent 
files aren't implemented in XML? The recent thread confusing the filename 
encoding scheme suggests that a human-readable, extensible, 
self-documenting format, one with many off-the-shelf tools available, would 
be better than a new binary format.

What constraints make the binary format preferable?

BTW, the archives don't show any previous discussion of XML:

<http://groups.yahoo.com/group/BitTorrent/messagesearch?query=xml>


 
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