I would prefer to pay with Paypal. I refuse to type my credit card details anywhere except payment processor's sites that I know I can trust. I am aware that the payment details input is inside an iframe but having to check page source to see that it's actually stripe is not something I think websites should expect their users to do. And I'm sure there are ways websites could still trick users, even if it appears to be a legitimate iframe in the page source.
Completely anonymous payment options would also be appreciated. I know Kagi promises not to associate search data with the account, but relying on trust is not a good model long term. It would be better to have an option to avoid providing any personally identifiable data in the first place.