Yes, it has led to actual, paying jobs. It takes some management on my part, but it's a lot easier than hunting around from site to site, or going to meetups, or any of that other stuff.
Do I get spammed? Sure. That's why I have a specific email account for them. Some of the spam is quite informative. I learn about openings early on, and can often find the hiring company by taking the text of the spam and searching the various job boards.
I get genuine requests, too. I take the time to respond to those just as genuinely.
For all the talk of the importance of networking around here, I'm kind of surprised at the antipathy. It's very low effort, just a few minutes a week.
I regard a lot of the complaints as symptomatic of the overall industry. I finally started going to meetups, and the signal-to-noise is just as bad, if not worse.