Imagine a democracy in which you vote your IQ from an official test. If your IQ was measured at 114 your vote counts 114 times, etc. This seems obviously unfair. But would it improve the results? My intuition fails me here, I can't predict. I wonder if that rule would have swung Brexit the other way? That would give an idea of the magnitude of the difference.
Several forms of "census suffrage" exist. https://en.wikipedia.org/wiki/Householder_Franchise (Check the other languages because they are more complete and better document the various forms).
Are there others who do it too?