A question and answer about BAT ads from reddit i think might be helpful
ANSWERED by Krylan:
BAT ads you are reffering to are not “blocked ads and tracking code”. What Brave Shield (lion icon) is blocking are current ads on websites. If you successfuly opted in Brave Rewards (BAT/triangle icon) you can see the ads in form of OS notification. Of course, there is no guarantee, that you will see them a lot, as it depends on advertisers and country they are targetting. This project is still developing, so there are not so many advertisers with active ad campaigns right now.