Why transformation?

This is a fairly basic question, I realize - but why is transformation
needed in a style language?  I'm having a damn hard time coming up with
good reasons why transformation and formatting actually belong together,
and can't find good reasons to push XSL over CSS for about 90% of the
applications I can envision.

Is there a good reason for this, or is it just that XSL has transformations
because DSSSL did?  There must be something more to it than the comfort
level of those used to working with SGML tools, but so far, I haven't heard
much exciting.

Where does XSL fit in an XML application architecture?
Why is this more more useful than CSS?
What is the value of conflating style and transformation?

Thanks.  I'm attempting to write an overview chapter on styles, and can't
find any great reasons to tell people to use XSL.

Simon St.Laurent
Dynamic HTML: A Primer / XML: A Primer
Cookies / Sharing Bandwidth (November)
Building XML Applications (December)
http://www.simonstl.com


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