Earlier quoted context omitted.
It wastes your time because it's full of cruft. And you cannot assume to trust it will solve your problem, so you're risking losing even more time.
While I'm not about to defend AI blog spam, what you just said it completely applicable to human-generated blogs as well. You should not just assume something is trustworthy or will solve your problem just because it was written by a human. And I have read plenty of cruft-filled blogs/articles/etc. from humans.
It kind of depends on the subject. If the blog is about politics, say, then you may assume that the human author is likely to be willing to lie. If it's about a non-contentious subject, though, then it is highly unlikely the human author will lie, and if they don't know, then, well, okay, _some_ people will write articles about stuff that they don't understand, but it's not common. Most non-psychopaths, if they don't know the answer, won't just make something up.
Whereas the magic robot will very happily spew nonsense on any subject.