There's a lot to unpack here.
Lets start with the attempt to define "usefulness" as the degree to which connection to humans happens. Human connection on the internet has always been illusory. Yet we still find utility in it.
"Trusted sources" have always been 100% biased in favor of whoever owns them. We all have equal free speech rights, but some of us are more free than others because the ability to purchase a bigger megaphone scales with access to capital.
Organized, capitalized propaganda farms existed before LLMs and have been engaged in the same kind of destructive information warfare. LLMs seem to be more persuasive than the wage-slave humans employed by troll farms and other mass media outlets, but that's not necessarily a bad thing if it manufactures a more rational public opinion.
LLMs lower the capital requirement to begin competing in the propaganda war. The biggest players who could afford to buy enormous media empires and fund human-generated influence operations are going to have to compete against the rest of us.
This planet has been a soulless hellscape longer than any of us have been alive, and LLMs are more likely to improve the situation than make it worse.
I suspect website owners will continue to shoehorn in whatever-the-fuck they want to and call it "strictly necessary".
What we really need is a Reject ALL-even-if-it-breaks-the-website button.