firebase - What are the benefits of using a root collection in Firestore vs. a subcollection?

Question

With the advent of collection group queries, it isn't clear to me what benefit there is in using a root collection. In this article by the Firestore team, the only things that I can see is that there is a possibility of name collision, the security rules are slightly more complicated, and you have to manually create any query indices. Are there any other reasons to use a root collection and not subcollections / collection group queries?

Answer 1

Waitting for answers