Thinking in a production pipeline based on OTS -> Texture -> Final Version.
Be the reference metadata retrieved by Crossref, parsed by Cermine or MeTypeset, we still need a good display version of the references for publishing matters.
In most of the cases the parsed references have glitches of metadata that must be fixed before publishing any content, increasing the publishing time.
Including the original textual reference in the metadata allows publishers to implement more flexible production steps separating publication issues from the production of quality metadata for data analysis, dissemination, including developing their own automated quality control for the given structured data.
There is a related ticket in texture to deal with untagged references: substance/texture#412
The basic idea is to have both metadata (structured, unestructured in the same element-citation).
<element-citation>
...
<styled-content specific-use="display|print|..." style-type="vancouver|abnt|iso">
Reference.....
</styled-content>
</element-citation>