I mean a lot of projects still come and go there (removing the idea fact that some of them are just shit projects), you can just copy-paste whatever you usually post to advertise on other social media platforms. Payment wise you just have to sort it out, just like how you would if it were in other places really. I reckon there's still some sort of traffic that comes with it, and search engines should still be able to pick up traction. It is for a fact though that a majority of old timers probably don't participate in bounties anymore (they might still look at the section sometimes), but new ones probably still linger around there.

Anyway I don't think it'd matter much in the long run, especially if you're project was good and legit. Adding promotions of it here in the forum can just be a small boost, after all, you'd better use whatever you can imo.