I've been on LinkedIn for a while, and I don't mind it for what it is. I have not taken a job that started with LinkedIn, but it has given me leads, multiple interviews, and an offer at one of the big tech companies. On most of my job applications I've attached my LinkedIn, but I doubt it does anything as all that info is on my resume.
Secondly I appreciate seeing my childhood, college, and ex-coworker friends' careers progress. I like knowing where they're at and what they're working on, and a LI update from someone I know has sparked lots of conversations.
As far as content, we all know it's worse than any other platform. I roll my eyes at over half of the things on my feed. But sometimes I find good article shares that aren't just marketing, and occasionally there's an actually interesting post. However I think they do a good job of showing you your connections' updates from a few weeks ago even, which is great for not following your feed constantly like Twitter.
I agree it is not at all necessary for finding a job, and I don't use it as a normal social media where I expect interesting content. So I definitely understand anyone who decides not to use it. But I've found value in it myself, and I certainly don't think it's doing me harm. The author never explains what the "harm" is.
I think this sentence in the article sums it up:
"It doesn't really matter, but that's not a world I want to participate in."
OP wrote an article about deleting an app that no one thinks is essential.