It applies not to Bibframe, but to a broader range. Collation ordering is not part of RDF, but of retrieval languages.
There was a discussion about a new keyword "collate" in SPARQL's "order by" but I do not know the current state. As long as there is no collation support in SPARQL, it is no possible to sort Bibframe literals e.g. in german "telephone book" order (W3C language tag de-DE-u-attr-co-phonebk) I have implemented phonebook order in Elasticsearch with ICU collations and JSON-LD literals, so I don't care too much about SPARQL.
I would appreciate it to see the Bibframe project more like a platform - implementors need a platform approach, elements/vocabulary and discussions about fields and values and how they are linked is not enough. This is too MARC-like.
Such a platform project would require to collect "best practice" approaches, in a kind of a guide, useful for being referenced by implementors. E.g.
- how to read and write Bibframe
- how to retrieve Bibframe
- how to sort Bibframe literals
- how to update Bibframe resources
- how to consolidate (match/merge) Bibframe resources
- how to ...<insert your problem here> ... with Bibframe
The question is, will this guide demonstrate how much easier it is to implement Biframe than MARC, and how easy will it be to find out about the"Bibframe compatibility" of a platform?