Brave uses Privacy Pass to separate your payment from your actual usage of the service, so they shouldn’t be able to link your payment info to your activity.
Honestly, it’s not the most private. That would be a service like Confer or Tinfoil Chat which use a Trusted Execution Environment on the server to answer your prompts without the provider being able to actually see your prompt or the response.
“Ask Brave” only promises that once you get the answer from the AI, it is encrypted with a key saved in your browser (so they can’t read it) and auto-deleted after 24 hours of inactivity. At least that’s my understanding of it, I could be wrong. I think Proton Lumo is similar.
This is still better than ChatGPT, Claude, Grok, Gemini etc. who can read your chats and even if you delete chats they’re not actually deleted from their server for another 30 days or so.
But I think Ask Brave actually gives really good answers, it’s always up to date (in fact better than Perplexity in many cases) and it’s pretty much unlimited and all free. So it’s definitely a great option and a good balance of privacy and quality. Personally, I really like it.