Difference #1 - Flexibility - in Kagi you choose any model you want to work with, not just models from one company

Difference #2 - Quality - Kagi Assistant uses Kagi Search. Ultimately, model quality will converge to the same place, quality of search results will remain a major difference.

Difference #3 - Privacy - Using models through Kagi is more privacy respecting due to non-training for API calls.