I think big business it's also a way of keeping in contact with former colleagues so that when you're interested in jumping to another company you can do it easily in one place.
Otherwise it's a place for sales people to pump out garbage posts.
If feels cringy and disgusting, apologies to engineers here who worked hard on that but that has no place in anything related to professionals and careers. I go there once every few years, do accept meaninglessly on all new connections and log off, ignoring all other parts. If I lose the job I'll update profile but otherwise the same.
In any case, the best advice I got on LinkedIn was from a mentor helping me find my first SE job who told me: You don't have to like it, but you would be stupid not to use it.