Subjectively, plant and animal searches feel starkly more superficial (using one use case). It's easy to see with a basic search like "Schizachyrium scoparium", which (iirc) previously returned much more material for the specialist concerned with this species's role in wild habitat from academic and government sources rather than a completely boring laundry list of nurseries, botanical gardens, and such just rephrasing the same basic info. Many of these sites would be ones I'd normally Lower in my results ranking, even.
With DuckDuckGo showing me essentially identical first page results for the above search, for me this experiment renders Kagi almost an Abridged version of DuckDuckGo results without even recourse to seeing More Results at the bottom of each page. This seems a massive handicap, particularly if Lenses don't improve quality of results by much (which they do not seem to be doing for me, here).
On a scale of 1-10, I might give 5 or 6. I'm aware that most of my searches each month probably don't need advanced search capabilities (that is, almost any search engine will probably give me what I want a good chunk of the time), and I'm keen on the people behind Kagi, having a UI devoid of clutter and ads, as well as privacy features like the image proxy and the graceful degradation that allows search to run without javascript enabled. But I'll admit being stuck with results like these going forward would dim my enthusiasm for Kagi search since it would no longer be my primary go-to for more specialized information, and as such I'd be much less likely to recommend it to others.