Its the browser that blocks ads, then replaces them with its own. Thats what they call a reward system. Then, as a website owner, you can accept Braves Terms and Condition and get your missing ad revenue as BAT, a worthless joke currency.
Its also the browser that displayed popups claiming you could donate to that youtuber if you viewed his channel, even if the youtuber did not have a brave account and by this did not accept Braves terms and conditions. This money goes automatically to brave.
Brave is nothing but a Scam Company.

Use a actually free as in freedom browser and just ad a FLOSS Adblocker like Ublock Origin, don't use this scam.

Edit: And just as an example how much of a joke BAT is, it is worth less then Dogecoin, something designed to be a joke.

The general idea of the browser isn't a bad one, it would be neat if consumers could direct their ad revenue to support specific content creators and media outlets. It is really hard to get people to donate their money even if they enjoy the content which they receive, one would think that people would find it much more easier to spend their ad-dollars than their hard earned, real world cash. As other commenters mentioned already, sadly Brave has some transparency/privacy issues, which undermine the whole project.

The idea itself would be good, but it has little to no transparency and lots of spyware