Smart move on BBC's part. They understand that the entire point of the Fediverse is to have your own instance that you control.

They'll never have to worry about the CEO of the Fediverse changing how it works and destroying their ability to communicate with the public easily (cough Musk & Twitter cough), and they're in full control of whom they federate with and what rules will be followed on their instance.

If every news organization and/or governmental organization had an ActivityPub, they wouldn't need Twitter or Facebook or whatever, period.