It's ridiculously expensive. It's not private if you have to link your searches to a paid account and none of those payment providers are private. They don't seem to have open sourced any of their key functionality, meaning you have to trust them to not be collecting your activity data.
I spent a long time getting rid of software and using services that I either no longer trusted or was unable to make an informed choice due to their lack of open source code and I'm not going to take a retrograde step now. And that's without the issue with their choice (a continued choice I believe) to use Brave results, a company I'm personally not prepared to support.