I'm seeing ads, but my wallet shows 0 BAT. Why?

You have 2 different BAT balances.

The balance you see when you click/tap the triangle BAT icon in the address bar shows your total balance, which only updates once per month during the payout period (generally the 5th to 8th of each month, but US holidays may delay the process).

Your other balance is your estimated pending Rewards, which updates in real time as you see ads.

You can access your pending Rewards balance by clicking/tapping the triangle BAT icon then "Rewards settings" (on Android it is just "settings", and you need to then click/tap "View Details" in the Ads section). Or you can navigate to brave://rewards on desktop or brave://rewards/ads on Android.