I did post my availability few times on HN "who wants to be hired" but with poor results and lots of wasted time (as again, the person on the other end does not know me or has worked with me everything gets bureaucratic again).
Also, all of the people I had hired for my clients came again from my network, there was never a public posting.
There's also other benefits, in general, you don't get to do silly technical interviews, as you're bringing former coworkers you can vouch for.
Not saying this can scale anywhere, but in smaller companies with good teams and professionals they always know someone from their previous jobs or their online communities (common in open source related githubs/discords/slacks) and I like it.