I think this is okay so long as you can toggle it off since now you apply userbase bias, which isn't guaranteed to be perfectly neutral, since it is bias in aggregate, anything remotely ideological in nature would be skewed one way or the other.
My understanding of is that it's just for you, not based on what every user of Kagi is choosing. Looking in the settings though I'm not sure if you can disable this feature on an ad hoc basis, which would be useful now and then if you want to get a fresh set of results and get out of your own biases.
I do like this idea however.