the article says:
"if you want to look up a DID:PLC, you need to query the Bluesky servers. This is important because every user is identified by a DID:PLC, and all interactions need to reference them."
which is not strictly true.
almost every user is identified by a DID:PLC but DID:WEB is also supported. DID:WEB is not mentioned in the article at all
I think this is important because it means that users can opt into being their own source of truth for their "identity" in the ATPROTO system