I think this quote from the paper (see VincentYu's link) gives a good summary of the findings and their significance:

The cognitive primitiveness of some of the processes causing the bias blind spot might be consistent with the failure of intelligence to attenuate the bias. However, this cannot explain the (albeit modest) positive correlations of the bias blind spot with cognitive sophistication that we found (see Table 2). The most likely explanation of this finding would probably be what we might term the “justified rating” account. Adults with more cognitive ability are aware of their intellectual status and expect to outperform others on most cognitive tasks. Because these cognitive biases are presented to them as essentially cognitive tasks, they expect to outperform on them as well. However, these classic biases happen to be ones without associations with cognitive ability.