The GCN app and player only started in mid 2020 when the season restarted after the first big lockdown. Certainly in the UK the GCN racing facebook page preceded this and that year the Herald Sun Tour and the Tour Down Under were broadcast live on that page. For those the host commentary was used, though if the same is done next year with the gcn player then I wonder if they'll use their own commentary now they have Robbie McEwen in the ranks.
GCN seems to have taken over from a lot of the ES Player stuff. And if you have ES Player, you get access to the stuff on GCN.
I used to watch a bunch of races in English because I couldn't figure out how to find Danish commentating for the non-interrupted streams.