Where Dan summarized and updated this in January basedon Lydia's feedback. And its also much easier to express and maintain mappings in Wikidata :)
So that is 2 votes so far to use the Statement "exact match" P2888, and not link the concepts between the two using the Identifier construct.
I await a few more thoughts and reasons why NOT to use an Identifier? I am looking at the nice hierarchy here on talk for Identifier https://www.wikidata.org/wiki/Talk:Q853614
and my personal thoughts are that Schema.org Type and Property can be looked at in 2 ways in Wikidata, as an Identifier and as a Concept, so.... ?