I made my profile look like my resume. And then tweaked it until the inmail I got was for jobs I wanted.
Part of it comes down to knowing how to write a good resume, the other part is gaming the keywords so your profile shows up in a good recruiter's results.
I still responded to every single message though because I'm pretty sure engagement metrics makes you more/less visible to prospective recruiters.
Got my previous job because I was easy to find on LinkedIn. Got my current job on a different continent by contacting people through LinkedIn. Yes there is a lot of of bullshit but it can be pretty useful too.
Might just be my industry (Accounting/Finance), but LinkedIn has also been great for me.
The first job out of college is always the hardest. I spent months sending out hundreds of resumes for a dozen interviews. But each job since then, I've only had to send out two or three before I had an offer.
Oddly, I'm back working for the same company I started at. I could be making more by job-hopping, but I realized that once I'm making enough money, I would rather take a pay cut then have the increased stress, poor benefits, and longer hours.
I think LinkedIn works best for somewhat specialized workers with higher education, credentials or specialized experience. I too have found my last two jobs there. It was useless for years but I recently hit a threshold apparently and it suddenly has become a good resource.
Wisdom! I get bored after a couple of years, so I'm mostly chasing the adventure, so I have changed industries and country recently without earning more.
Not OP, but I use Google Jobs where they aggregate jobs from every job website. I have around 40 job keyword alerts and get the daily new jobs in a 50 km radius. The only bad thing about this are the duplicates from similar keywords, so I wrote a python script that creates an Excel file with unique jobs from the mails and the most important job information.
I had this problem myself and really don't understand why this is so hard to find. My wife used a year ago and I wasn't able to find this feature again, so I looked in her browser history and found it. There isn't even a short accessible link, I can give you only this. Fill in your keywords, set the radius and in the lower left you can activate the alert. You need to be logged in with a gmail though to use the alerts.
Also it may not work on mobile and sometime I have problems with Firefox as well. If you want to be sure use Google Chrome on a desktop for this. I wouldn't be surprised if this is another stab to Firefox users.