I'm using search by similar images time to time to find an image with better quality. However Kagi's "find similar images" feature doesn't work as well as Yandex's feature and I frequently encounter that Kagi do not find anything and Yandex find 4-5 sizes of the image of my interest.
Here is an example image:

Kagi will only say me:
We haven't found anything.
There are no results for the given query.
Try a different image.
With a lonely dog looking at the horizon, but yandex will find this image with better quality.
Kagi should be better than yandex, not worse.