I think there are three functions to LinkedIn.
First, as a rolodex. It's pretty handy this way, though their search function is absolute shit.
Second, as a way to connect with new people. Again, pretty useful, though it's annoying to be on the receiving end of a flood of connection requests from seemingly random people without context.
Finally as a social media platform.
On the consumption side the noise:signal ratio is pretty bad. There's a ton of self-aggrandizing BS, an increasing amount of politics, and just low-quality garbage. I scroll through it most days for a bit and usually find something of use about an emerging topic in my field. That said, I work in a highly dynamic field (cyber). If I worked in something more static, I'd find the feed far less useful.
On the production side, it's a convenient platform. I just recently posted an article I had published elsewhere (read: not a #deepthoughts twitter regurgitation). I got pretty decent engagement and some feedback that made me smarter on the topic I wrote about. I also got a bunch of additional connection requests for whatever that's worth. And my company is happy for the exposure.
So... use it for it's strengths, but don't expect every aspect of it to be brilliant.