Voting yes because it's a not a one-way street with a lot of benefits. If someone finds success because they got a spotlight from the forum then that's just a stronger ally on your side.
Grass-roots entrepreneurship and being able to say "that massively successful project that a lot of normal non autistic people like got it's start on kiwifarms" really does legitimize the site, much like the SA alumni that was put together for the Lowtax stream.
I think most people are only adverse to advertising if it's completely worthless zog slop like temu banners or some Amazon scam garbage. Completely different ballpark than something like "guys I made a game/comic book/music/open source project come check it out".
I don't really see a massive negative outcome from this. worst case scenario a grifter slips through the cracks and gets publicly shamed and ridiculed by the entire site afterwards, best case scenario you can be a part of history if something really takes off. You've gotta be a real low IQ retard to publicly expose your taint to the farms in hopes for cash, and not expect to be doxed and ridiculed until the end of time for trying to pull off some scam.
There's also already a precedent for spotlighting other free community projects (the doom wad, the SS13 server, crunklords TempleOS games, etc). Not exactly the same thing as promoting a commercial product you intend to sell, but not that far off either imo.