19.778 - Note - "This XML structure simplifies [XSLT] transformations because XSLT only acknowledges the conditional style if the formatting attributes are relevant." acknowledges?
I think it means that text:style-name attribute contains the name of the style (result of the conditional evaluation) and text:cond-style-name contains the name of the conditional style. Both of which are true but also stated elsewhere.
I suspect the note is meant to say that an XSLT transformation can use text:style-name and ignore text:cond-style if it wants to.