Not worth even the hour of my time it would take, or I would have done it four years ago. (Ironically, using minisites to get ten slots on a SERP is bad to Google's view of the world in a way that serialz are not.)
It is just the psychic nuisance factor: every time I see that box it's like "Come on guys, really?"
You probably haven't investigated, but I'm wondering if any of those are actually what they claim to be, or more likely just malware payloads. It's quite common for the black hats to shotgun-distribute a malware trojan labeled as a crack or serial for thousands or millions of software titles.
(I am resolved to only ever get burned by that once...)
It is just the psychic nuisance factor: every time I see that box it's like "Come on guys, really?"