Ah, I see what you mean. Those are people who are trying to get around the actual Fiverr rules. They get lots of responses because some sellers are really desperate. Since Fiverr doesn’t allow you to bid on a buyer request with commissions or percentages, they can’t actually go through with what they are describing. When they get offers what they are probably doing is asking the bidder to contact them outside Fiverr to make arrangements and they will get banned by Fiverr for that when they are caught.
It’s a shame, really, because there is nothing wrong with buying real promotions and some of them might actually help you. For example, I used to have a gig offering to write a prank news article for people. In order to get views, I found a Fiverr seller who had a blog about pranks and I bought a gig from them and had them advertise my gig on their blog. It did result in increased impressions for me. There are plenty of realistic gigs you can buy for all sorts of promotions, but they would all be in normal Fiverr prices starting at $5.
There are tons of things in buyer requests that shouldn’t be there, from people asking for services that aren’t allowed (like adult-only photos) to sellers putting gig ads where buyer requests belong, but those are all useless and just end up with the users in trouble. If you are really interested in promoting your gigs, try look around in the Marketing section.
There are other valid things as well, like actual SEO services to drive traffic to your gig, but if you want that you’d need to choose very carefully since most of them are selling bot traffic or bad backlinks that won’t convert to actual sales. (I’m not saying all SEO services are bad by any means, just that if you aren’t sure about what you are buying, there are safer ways to advertise.)