A compelling use case for employing binary trees in XM

Hi Folks,

Dimitre has created a beautiful set of functions for building binary trees
[1].

I understand that binary trees can be used to sort data. But XSLT already has
<xsl:sort>, so using binary trees for sorting isn't a particularly compelling
use case.

I am seeking a compelling use case for binary trees -- given XML document
foo.xml and processing requirement P, a binary tree is ideally suited.

Would you provide a simple, compelling use case please?

/Roger

[1]
http://dnovatchev.wordpress.com/2012/01/09/the-binary-search-tree-data-struct
urehaving-fun-with-xpath-3-0/