According to the article, Eich will pay you in a "cryptocurrency" which cannot be exchanged for cash.
> Brave will give users a 70 percent cut of its advertising revenue, which Eich estimates could work out to about $5 a month. Brave will pay users with its own bitcoin-style "cryptocurrency” called Basic Attention Tokens or BAT, which has traded for as little as 12 cents and as much as 46 cents over the past 12 months, according to CoinMarketCap. Today, there’s no way for users who receive BAT for viewing ads to swap their digital currency for dollars, but Eich says Brave will partner with cryptocurrency exchanges to make that possible.