I haven't used feedle enough to vouch for the quality of their results. I wouldn't know how to check if their list of results is comprehensive.
Usually, I can find the same sites by fishing them out of a Kagi search, but it requires some effort as everything comes mixed with other search results.
I do like that feedle returns a filtered list with just blogs and podcasts. I assumed that these same sites are already in the Kagi full index, and they could just be filtered out for the user.
In addition to the filtered list of podcasts and blogs, a useful feature of feedle that is not existent in Kagi is an RSS feed that can be pasted into a newsreader, for instance. However, I'm uncertain if supplying an RSS feed would be within the capabilities of Kagi.
So, in short, it would be useful to have feedle inegrated in Kagi provided their results quality match the quality of the rest of Kagi Search.
By the way, thanks for making Kagi. It's a delight to use!