The GP means that the journalists at the TV stations are getting their leads on what to cover from Twitter; not that audiences are watching Twitter in place of breaking news.
They probably have a police scanner running too. Should the public have that running as well to listen to all the latest news? IMO there is place for that and most people don't really need up to the second information on things happening hundreds of miles from anywhere they regularly interact with.
Who said anything about the public? A "breaking news platform" being of relevance to journalists is valuable enough for it to be a large company; whether anyone from "the public" makes direct use of it, they still indirectly depend on its existence.
