centralized platform full of bots looking for certain keywords to then spam people offering shitty jobs to people who don't know better. at least as a dev, it was completely pointless. i would just get hit up by recruiters all the time for shit i don't do anymore of have never done because it's all "automated." i never got any job or found anything interesting on there. i also had a friend that did any experiment where he made up a fake person and farmed fake reviews from people and he started getting all kinds of job offers and such.
if you want to get a job you actually enjoy, my recommendation would be to do a little bit of networking in person at meetups and actually build things. don't depend on rando messages on linkedin.