Use of dcterms:hasPart and dcterms:isPartOf

[hm-raws]

Hello,
I was wondering why you have chosen to assign the dcterms:hasPart and dcterms:isPartOf properties as superproperties of the igeo:subdivision and igeo:subdivisionDe properties, given that the dcterms vocabulary is for describing metadata, not spatial relations? I wonder whether it would be more appropriate to use geo:sfContains and geo:sfWithin instead? I would like to reuse the insee-geo ontology but I find this point to be problematic.
Thanks in advance for any insights you may have!