The answer, of course, is that self-enhancement and projection are separable tendencies. One can judge desirable traits as being more descriptive of oneself and of another person than undesirable traits. This assumed similarity expresses projection. At the same time, one can judge desirable traits as being more descriptive of oneself than of the other, and undesirable traits as being less descriptive of oneself than of the other. These discrepancies express self-enhancement.
Rationality is intelligent.
On the perception of social consensus. Intelligence is not rational. Individual differences in cognitive biases. Individual differences in rational thought.