There's also companies who are posting things like "Hey we won some irrelevant award yay us." Or more likely, employees posting this about their own as a public signal that they are "all in" on "company."
It's mostly for signalling for especially aspirational people. But generally speaking, 99% of the utility of LinkedIn is to have a public resume so recruiters can find you. At least in my case.
A coworker has at times referred to me as a LinkedIn Shitpost Memelord, although I don't use image macros/memes. I just share information about a very niche corner of the internet, and it's way more effective than advertising. It actually serves as an outlet for the kind of writing I used to do, and sometimes still do, on forums - but instead of being about music and bands, it's about commerce and software. It's weird, but it scratches an itch I guess.
I do see more 'social' posts on LinkedIn, and it's pretty close to the worst of the net. It's like YouTube comments, except you can see the people who post them all wear suits in their photos. A surprisingly large number of people who like & reply to self-help garbage, effusively, as though Gary Vee's latest you-can-do-it schlock saved them from offing themselves at the water cooler that morning.
This is sad, but as someone who will happily admit failures, frustrations and annoyances on LinkedIn I have been in interviews where people have dinged me heavily for it. So far these have all been quite toxic work environments - maybe you could count it as a useful filter, but I understand given this why people feel pressure to do little more than copy/paste the same Oleg posts ad infinitum.