It's easy to make claims when it comes to evolutionary biology - there's patterns everywhere - but it's almost impossible to prove anything, and most of the things that are "obvious" won't turn out to be true.

As a counterpoint, there's loads of things that get humans high that don't have any obvious benefit, why shouldn't other animals be the same?

And there's certainly loads of other plants that work just as well as pesticides, and yet they don't get cats high.