How useful is chunker.output.indent?

How useful is chunker.output.indent?  I noticed that it randomly indents
contents of elements where whitespace matters, such as <pre> in HTML
output.  That cannot possibly be useful except in the most trivial
documents.  Also, the non-chunking stylesheet html/docbook.xsl doesn't
even support turning on indent in xsl:output.  Is there any reason why
the chunking stylesheet supports it?