Vote selling and circular voting themselves aren't bad and can't be stopped in any case. So we posit that as a given. Vote selling, etc. that results in payouts divorced from content value is the problem, and can be countered with downvotes as long as it is highly visible which is why some form of superlinear is needed (I'm not arguing for this specific curve or parameters; at this point I'm not even sure I correctly understand what they are).